"Considering the global patterns of Facebook usage, demonstrating mobile ad revenue acceleration is critical for the company. There were 819 million mobile monthly active users on Facebook as of June 30, up 51% over the previous year. That's 71% of the total who access the social network at least once a month.

The bottom line is that although desktop affords much more real estate for ads, including a whole right rail that's missing from the Facebook mobile app and is mainly embraced by direct-response advertisers, fewer and fewer users will be logging in to see it.

Facebook's performance last quarter was largely driven by marketers growing their budgets for news-feed ads, which see higher click-through rates than ads on the right rail, according to chief financial officer David Ebersman. He also observed that news feed ads are expected to be the main driver of Facebook's revenue growth in the second half of the year and that ad prices in the U.S. and Canada increased 40% year over year."

1) So I wonder if/when advertising encroachment will deter user engagement.  The "point" at the end of "at some point" is a magical tipping-point quant.

"Mr. Zuckerberg obliquely addressed the criticism that the Facebook news feed has gotten too commercial. He said that about 5% of news-feed posts seen by users are ads, and there's been no observed drop-off in satisfaction. However, he acknowledged that Facebook will continue watching user reaction closely.

'In recent studies people have told us they've noticed the ads more, so we're going to invest in improving the quality,' he said."

and

"Facebook executives didn't address Facebook Home or the company's long-awaited autoplay video ads, which Ad Age reported were in development last December. The units could contribute materially to revenue IF MARKETERS  PUT CONCERNS ABOUT DISRUPTION TO THE FACEBOOK USER EXPERIENCE ASIDE AND ADOPT THEM. (caps mine). The asking price was into the seven figures for a day-long "slot," but they're now delayed until the fall." 

2) Explains Karp's ad love.