The Renren-backed social media platform has formally announced it will shut down this week, with Square paying about $1m for some of its engineers and IP.

Yik Yak, the US-based anonymous social media app that raised $73.5m from backers including social media group Renren, is shutting down this week, according to a blog post by its co-founders.

Founded in 2013, Yik Yak built a university campus-based app that acted as an anonymous online community message board. It grew quickly and secured $62m in a November 2014 series B round led by Sequoia Capital that valued it at between $300m and $400m.

Renren had contributed