Meerkat hires former Tumblr's head of media and partnerships, Sima Sistani (L) and Twitter's former head of media Chloe Sladden.

Meerkat is preparing for a mainstream push.

The livestreaming app that took off around Austin's South By Southwest conference back in March has made two significant additions to its executive team. The company hired Sima Sistani, Tumblr's head of media and partnerships, as its new VP of media, content and community. It's also bringing on Twitter's former head of media, Chloe Sladden, as an official adviser. The news was first reported by the Hollywood Reporter.