Instagram has overtaken Twitter to become more popular with US smartphone users, highlighting the rise of the Facebook-owned photo-sharing app as it begins to sell advertising. Nearly 35 million Americans used Instagram at least once a month last year, compared with 30.8 million using Twitter’s mobile app, according to estimates from E-Marketer, the research group.

Move over, Twitter. Photo-sharing service Instagram is now approaching the user levels of the older micro-blogging service. Almost 35 million Americans used Instagram at least once monthly in 2013, according to research firm eMarketer, compared to 43.2 million for Twitter. Instagram is heavily tilted to younger users, while Twitter’s user base has begun to even out among age groups. And, although more males are coming aboard, Instagrammers were 59 percent female last year. Twitter was nearly even. A younger, more female and more socially active user base may be finding Instagram a more hospitable service.