This is the latest citation management tool (including a bibliography generator) from ProQuest, which brought us RefWorks. Flow allows you to manage and organize your citations, like RefWorks, while also making it easier to read, annotate, and collaborate on documents. (See this YouTube Video for a general introduction to Flow.)
To create a Flow account, you'll just need to provide your e-mail address and create a password. Once you've created an account, you can then go to Flow to get started.