RefME is a great service for organizing your research and creating bibliographies out of your collections of online and offline resources. I've been a supporter of the service since I first tried it a few years ago. It appears that I'm not the only one who likes RefME because it was recently acquired by Chegg. Chegg is rolling RefME into their existing bibliography generator called Cite This For Me.
RefME will become Cite This For Me next week. Starting on March 7th you will have to go to http://www.citethisforme.com/premium/login. As that URL indicates, there is a premium version of Cite This For Me. If you don't purchase the premium version, on June 1st you will access to your existing RefME projects. The free version of Cite This For Me only allows you to store your projects for seven days before they are deleted.
A couple of alternatives to RefME and Cite This For Me are refDot and Easybib (I like the Google Docs Add-on they offer).