We recognize revenue in accordance with ASC 606, “ (“ASC 606”). ASC 606 is a comprehensive revenue recognition model that requires revenue to be recognized when control of the promised goods or services are transferred to our customers at an amount that reflects the consideration that we expect to receive. The application of ASC 606 requires us to use significant judgment and estimates. Application of ASC 606 requires a five-step model applicable to all revenue streams as follows:

 

When another party is involved in providing goods or services to our customer, we apply the principal versus agent guidance in ASC 606 to determine if we are the principal or an agent to the transaction. When we control the specified goods or services before they are transferred to our customer, we report revenue gross, as principal. If we do not control the goods or services before they are transferred to our customer, revenue is reported net of the fees paid to the other party, as agent. Our evaluation to determine if we control the goods or services within ASC 606 includes the following indicators:

We capitalize commissions paid to sales personnel in our self-publishing business when customer contracts are signed and advance payment is received. These capitalized costs are recorded as prepaid commission expense in the Consolidated Balance Sheets. The amount capitalized is incremental to the contract and would not have been incurred absent the execution of the customer contract. Commissions paid upon the initial acquisition of a contract are expensed at the point in time that related revenue is recognized. Prepaid commission expenses are periodically reviewed for impairment. At December 31, 2019, our prepaid commission expense was $0.6 million.

two-years

Significant changes in our contract liabilities balances during the period are as follows:

 

 

We expect to satisfy these performance obligations as follows:

 

two-year

Our self-publishing contracts may exceed a one year term due to the length of time for an author to submit and approve a manuscript for publication. The author may pay for publishing services in installments over the production time line with payments due in advance of performance. The timing of the transfer of goods and services under self-publishing arrangements are at the discretion of the author and based on future events that are not substantially within our control. We require advance payments to provide us with protection from incurring costs for products that are unique and only sellable to the author. Based on these considerations, we have concluded that our self-publishing contracts do not contain a significant financing component under ASC 606.

Similar to former revenue recognition guidance, we continue to make significant estimates related to variable consideration at the point of sale, including estimates for refunds and product returns. Under ASC 606, estimates of variable consideration are to be recognized before contingencies are resolved in certain circumstances, including when it is probable that a significant reversal in the amount of any estimated cumulative revenue will not occur.

pre-determined

Based on the constraints for using estimates of variable consideration within ASC 606, and our historical experience with these campaigns, we will continue to recognize revenue at the base amount of the campaign with variable consideration recognized when the uncertainty of each campaign is resolved. These constraints include: (1) the amount of consideration received is highly susceptible to factors outside of our influence, specifically the extent to which our audience donates or contributes to our customer or programmer, (2) the length of time in which the uncertainty about the amount of consideration expected is to be resolved, and (3) our experience has shown these contracts have a large number and broad range of possible outcomes.

In broadcasting, trade or barter agreements are commonly used to reduce cash expenses by exchanging advertising time for goods or services. We may enter barter agreements to exchange airtime or digital advertising for goods or services that can be used in our business or that can be sold to our audience under Listener Purchase Programs. The terms of these barter agreements permit us to preempt the barter airtime or digital campaign in favor of customers who purchase the airtime or digital campaign for cash. The value of these exchanges is included in revenue in an amount equal to the fair value of the goods or services we receive. Each transaction must be reviewed to determine that the products, supplies and/or services we receive have economic substance, or value to us. We record barter operating expenses upon receipt and usage of the products, supplies and services, as applicable. We record barter revenue as advertising spots or digital campaigns are delivered, which represents the point in time that control is transferred to the customer thereby completing our performance obligation. Barter revenue is recorded on a gross basis unless an agency represents the programmer, in which case, revenue is reported net of the commission retained by the agency.

Trade and barter revenues and expenses were as follows:

 

We have elected certain practical expedients and policy elections as permitted under ASC 606 as follows:

 

 

A summary of each of our revenue streams under ASC 606 is as follows:

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1

2

50-minutes

. We recognize revenue from the sale of airtime to local and national advertisers who purchase spot commercials of varying lengths. Spot Advertising may include variable consideration for charities and programmers that purchase spots to generate donations and contributions from our audience. Advertising revenue is recognized at the time of broadcast, which represents the point in time that control is transferred to the customer thereby completing our performance obligation. Advertising revenue is recorded on a gross basis unless an agency represents the advertiser, in which case, revenue is reported net of the commission retained by the agency.

Network revenue includes the sale of advertising time on our national network and fees earned from the syndication of programming on our national network. Network revenue is recognized at the time of broadcast, which represents the point in time that control is transferred to the customer thereby completing our performance obligation. Network revenue is recorded on a gross basis unless an agency represents the customer, in which case, revenue is reported net of the commission retained by the agency.

We recognize revenue from the sale of banner advertising on our owned and operated websites and on our own and operated mobile applications. Each of our radio stations, our digital media entities and certain publishing entities have custom websites and mobile applications that generate digital advertising revenue. Digital advertising revenue is recognized at the time that the banner display is delivered, or the number of impressions delivered meets the previously agreed-upon performance criteria, which represents the point in time that control is transferred to the customer thereby completing our performance obligation. Digital advertising revenue is reported on a gross basis unless an agency represents the customer, in which case, revenue is reported net of the commission retained by the agency.

Broadcast digital advertising revenue consists of local digital advertising, such as the sale of banner advertisements on our owned and operated websites, the sale of advertisements on our own and operated mobile applications, and advertisements in digital newsletters that we produce, as well an national digital advertising, or the sale of custom digital advertising solutions, such as web pages and social media campaigns, that we offer to our customers. Advertising revenue is recorded on a gross basis unless an agency represents the advertiser, in which case, revenue is reported net of the commission retained by the agency.

During 2018, we launched a national multimedia advertising agency with locations in 34 markets across the United States. Salem Surround offers a comprehensive suite of digital marketing services to develop and execute audience-based marketing strategies for clients on both the national and local level. Salem Surround specializes in digital marketing services for each of our radio stations and websites as well as provides a full-service digital marketing strategy for each of our clients. In our role as a digital agency, our sales team provides our customers with integrated digital advertising solutions that optimize the performance of their campaign, which we view as one performance obligation. Our advertising campaigns are designed to be “white label” agreements between Salem and our advertiser, meaning we provide special care and attention to the details of the campaign. We provide custom digital product offerings, including tools for metasearch, retargeting, website design, reputation management, online listing services, and social media marketing. Digital advertising solutions may include third-party websites, such as Google or Facebook, which can be included in a digital advertising social media campaign. We manage all aspects of the digital campaign, including social media placements, review and approval of target audiences, and the monitoring of actual results to make modifications as needed. We may contract directly with a third-party, however, we are responsible for delivering the campaign results to our customer with or without the third-party. We are responsible for any payments due to the third-party regardless of the campaign results and without regard to the status of payment from our customer. We have discretion in setting the price to our customer without input or approval from the third-party. Accordingly, revenue is reported gross, as principal, as the performance obligation is delivered, which represents the point in time that control is transferred to the customer thereby completing our performance obligation.

. We recognize revenue from the sale of advertisements and from the placement of ministry content that is streamed on our owned and operated websites and on our owned and operated mobile applications. Each of our radio stations, our digital media entities and certain publishing entities have custom websites and mobile applications that generate streaming revenue. Digital streaming revenue is recognized at the time that the content is delivered, or when the number of impressions delivered meets the previously agreed-upon performance criteria. Delivery of the content represents the point in time that control is transferred to the customer thereby completing our performance obligation. Streaming revenue is reported on a gross basis unless an agency represents the customer, in which case, revenue is reported net of the commission retained by the agency.

e-books.

on-air

pro-rata

. We recognize revenue from the sale of books upon shipment, which represents the point in time that control is transferred to the customer thereby completing the performance obligation. Revenue is recorded at the gross amount due from the customer, net of estimated sales returns and allowances based on our historical experience. Major new title releases represent a significant portion of the revenue in the current period. Print-based consumer books are sold on a fully-returnable basis. We do not record assets or inventory for the value of returned books as they are considered used regardless of the condition returned. Our experience with unsold or returned books is that their resale value is insignificant and they are often destroyed or disposed of.

E-Commerce

re-saleable

. We recognize revenue from self-publishing services through Salem Author Services (“SAS”), including book publishing and support services to independent authors. Services include book cover design, interior layout, printing, distribution, marketing services and editing for print books and eBooks. As each book and related support services are unique to each author, authors must make payments in advance of the performance. Payments are typically made in installments over the expected production time line for each publication. We record contract liabilities equal to the amount of payments received, including those amounts that are fully or partially refundable. Contract liabilities were historically recorded under the caption “deferred revenue” and are reported as current liabilities or long term liabilities on our consolidated financial statements based on the time to fulfill the performance obligations under terms of the contract. Refunds are limited based on the percentage completion of each publishing project.

Revenue is recognized upon completion of each performance obligation, which represents the point in time that control of the product is transferred to the author, thereby completing our performance obligation. Revenue is recorded at the net amount due from the author, including discounts based on the service package.

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We recognize revenue from the sale of print magazine advertisements. Revenue is recognized upon delivery of the print magazine which represents the point in time that control is transferred to the customer thereby completing the performance obligation. Revenue is reported on a gross basis unless an agency represents the customer, in which case, revenue is reported net of the commission retained by the agency.

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on-air