between users and tweets, making it more likely for users to click through on its ad products. Now the pressure is on Facebook to create mobile advertising products that effectively utilize what seems to be Instagram's key strengths, according to comScore: Bringing users back more often on a daily basis, and keeping them engaged for a longer period of time compared to Twitter. We should note that until as recently as this summer, comScore did not provide a detailed information report on mobile metrics. Only in May did comScore first launch its Mobile Metrix 2.0 measurement product . It is not clear whether comScore's numbers will continue to reflect these trends in Instagram and Twitter use. Also of note is that comScore's data only measured activity from users age 18 and older, which no doubt cuts out a broad swath of minors who use both services. To some degree, it makes sense that users spend more minutes engaged with Instagram than Twitter. Instagram's never-ending flow of content is composed entirely of photos, with each picture requiring some degree of pause to take in. Twitter's stream, on the other hand, is primarily composed of text-based messages, interspersed with some embedded photos, videos and links out to other Web sites. In a way, Twitter is designed to make it easier for users to move speedily through the stream, stopping on text or pictures as often or as little as they like. Twitter has been trying to change this in recent months, however,