About 4 years after it launched Anobii was bought by a consortium consisting of the UK Retailer HMV and a trio of publishers (Penguin, Random House, HarperCollins). Anobii then changed hands again in June 2012, when Sainsbury's bought out HMV and acquired a majority stake. This UK retailer bought a 64% share in the social network for £1 plus the promise of taking over certain debt obligations.
About 7 months later, Sainsbury's revealed their intentions when they divided Anobii by splitting the existing community off from its ebookstore. That store was still under development as Anobii Beta, and it was intended to both be a source of funding for Anobii. It was also going to become the main Anobii site once development was complete.
That Anobii beta site is now known as eBooks by Sainsbury's, and obviously it sells ebooks. Both the back end and the website, as well as the related reading apps, were developed by the Anobii team. It would appear that Sainsbury's got what they wanted from owning Anobii, leading them to sell it less than 2 years after they bought it.
Mondadori is but the latest publisher to acquire or launch a book community; many US publishers, including Baen Books, Macmillan, Penguin Random House own one or more.