General Ad Requirements (apply to all ads)

• Interest-Based Advertising (IBA): Include IBA selfregulation controls for ads using behavioral targeting (5kB max file size). • Audio: Audio in ads should be muted. To allow for audio initiation in ads, a control may be included for the user to initiate audio. See the LEAN user experience and ad content guidance for more on audio in ads. • Defining ad space: Ad unit content must be clearly distinguishable from publisher or unpaid content on the page (for example an ad unit may have clearly defined borders so it is not confused with normal page content). • CPU Load: Ads should be developed to perform smoothly and not interfere with site or app performance. 30% CPU load max (based on the average CPU of the user base) per active ad. Please review the LEAN guidance for more details on CPU load. • Maximum number of host-initiated file requests: Ad must not exceed ten file requests during initial file load. Additional files can be loaded as necessary during host initiated subload and user initiated loads.

General Notes

• Initial file load: Includes all assets and files necessary for completing first visual display of the ad and requested before load event dispatched by the window object. • Host-initiated subload (subload): This is the additional file weight an ad can load in addition to initial load. Ad file subload may begin after the load event has been dispatched by the window object. The ad should listen for the load event dispatched by the window object of the host page. When communication with the host page is not possible, then it is acceptable to listen for the load event dispatched by the window object of the ad iframe. • File weight calculation: For calculating ad file weight, all files for the ad, including those shared libraries not exempt by the publisher or ad server, must be included as part of the maximum file weight calculation. File weights are calculated after files have been compressed into gzip format. Initial Load K-Weight= All ad files + Non-exempt shared libraries + max 50 kB for all exempt Shared Libraries Subload K-Weight = All ad files + all non-exempt shared libraries See the LEAN user experience and load performance guidance for