What’s a pop phenom and social networking maven to do after she tops 11 million Twitter followers?

Join Tumblr, of course.

The microblogging platform, which exceeded five billion posts and 17.5 million accounts last month, now includes Lady Gaga among its users. Christened ‘Amen Fashion,’ Gaga’s Tumblr is functioning — for now, anyway — as an outpost for pictures by and/or of the star, mostly in a series of typically attention-getting outfits.

Not surprisingly, there’s a huge audience for Lady Gaga photos; according to reports, her Tumblr’s launch triggered enough traffic to slow down the service’s entire network. The debut of ‘Amen Fashion’ comes roughly a month after her latest album, ‘Born This Way,’ debuted on top of the Billboard charts with over a million copies sold — the highest one-week sales tally in a decade.