There's a joke about "engagement" here somewhere. As most readers are doubtless aware the Supreme Court legalized gay marriage in all 50 states last week, and the reaction on social media was, well, enormous: according to Facebook around 26 million users changed their Facebook pictures to show a rainbow flag to celebrate the historic decision. And of course brands weren't far behind, as marketers capitalized on the big moment to boost engagement with social media posts showing their support for marriage equality.

We're well over a decade into the social media age now, and that means that a lot of people have had a lot of opportunities to put very ill-advised things online, learning only too late the tragic lesson that stuff lives forever on the Internets. "Ah, how terrible is wisdom when it profiteth not the wise!"

Facebook's Atlas system for targeting and measuring advertising has been live in its current from since September 2014, and there's a lot of anecdotal evidence about its capabilities, but this week a big advertising client -- ticket vendor Live Nation -- shared some specific details about its success with Atlas. The announcement was made, inevitably, at Cannes, but Facebook also shared some key insights on its Atlas blog for the rest of us uncool people.

In addition to making every photo look all artsy and brooding - look, it's a refrigerator, and it's depressed! - digital photo filters actually boost social media engagement, attracting more clicks and comments. That's according to a new study by Yahoo Labs and Georgia Tech University, first reported in the New York Times, which looked at more than seven million photos from Flickr, of which half originally came from Instagram.

Hold the phone! The federal government is producing more regulations -- shocking, I know -- and this week's batch includes new, more specific advice for social media marketing compliance from the Federal Trade Commission. Among other things the FTC updated its social media guidelines for the use of endorsements and testimonials.

Most advertisers still aren't exploiting Facebook data to its full potential, and the social media behemoth wants to change that with intensive training courses, according to a report in Bloomberg, citing remarks by Facebook vice president for global marketing solutions Carolyn Everson. The company is also bringing Facebook-style ad targeting to Instagram; both initiatives will be unveiled this week at, you guessed it, Cannes (P.S. everyone who's not in Cannes: party at my place!).

Pinterest is ramping up its advertising offerings through partnerships with a number of marketing develop partners (MDPs), who will help ad clients optimize and scale up their campaigns using Pinterest's Ads API. After announcing the program last month, the image-centric social network for enthusiasts has named the official MDPs as well as some of their launch clients.

Social media intelligence firm Crimson Hexagon has unveiled a new image analytics service as part of its ForSight analytics platform, the company announced this week. Among other capabilities the new product allows marketers to see how and where consumers are sharing images of their logos, even when the brand isn't mentioned by name.

Twitter is preparing to launch a major new feature, dubbed "Project Lightning," that allows Twitter and its users to aggregate content around events in curated spaces on the platform, including photos and videos, Buzzfeed reported Thursday. Project Lightning will also enable users to share the curated content outside Twitter by embedding them on other sites as well as within third party apps, according to the same report.

One of the big questions hanging over Snapchat is the issue of monetization, and specifically advertising, as it's kind of hard to imagine any ad format appearing around user messages that wouldn't be egregiously intrusive, given the inherent limitations of the medium. However the disappearing messaging platform may have struck on an ingenious solution, by offering users branded photo overlays -- for example virtual stickers and frames -- sponsored by contextually relevant brands.