Not very much I'd guess. That article says the product is being shut down, so this is much more of a hiring-with-bonus than a "real" acquisition. Another article says the yobongo investors will become mixbook investors, so it's possible they didn't even recoup the original investment in cash: http://thenextweb.com/insider/2012/03/08/photo-book-company-...
http://allthingsd.com/20120308/yobongo-which-launched-at-las...