Plasmid is an in-browser database and I've been working on it for a few months, talked to many people about it, and finally reached a point where I can release an API stable version.
There are two main components to Plasmid, developed separately. PlasmidJS is the in-browser database, based on the IndexedDB specification and supports recent versions of Chrome, Firefox, and Internet Explorer. The second component is Plasmid Sync: a backend server that allows users to synchronize their in-browser databases between machines.
I'm really excited about this and I hope to see what people can do with it. There are other projects like this around, most notably the excellent PouchDB project, but I think Plasmid has properties that make it a better fit for many needs.
This release is PlasmidJS 0.2.0 and is available at Github and on the Plasmid GitHub page.