Today techcrunch confirmed that Elsevier will purchase Mendeley for between $69-100M. For more on this see the techcrunch article – http://techcrunch.com/2013/04/08/confirmed-elsevier-has-bought-mendeley-for-69m-100m-to-expand-open-social-education-data-efforts/
Mendeley put out a piece on their blog talking about the coming changes – http://blog.mendeley.com/start-up-life/team-mendeley-is-joining-elsevier/