[whatts]

Can you explain why you would suggest CouchDB? Of course, it seems to be a great project. Nevertheless, it has no built-in support for publishing and subscribing, and real-time notifications.

We would have to built this ourselves. However, CouchDB has a "_changes" API that can even be turned into "continuous" mode [1]. This is the perfect data source for pub/sub.

hood.ie, Meteor, etc. offer more features, but they are also more cluttered and not as clean as CouchDB.

[1] http://docs.couchdb.org/en/latest/api/database/changes.html

[bgar]

Well I mean if you just want to use replace Firebase you might as well use hood.ie directly, unless you want to build it yourself (in which case using just the database and layering functionality on top of that might be best). Hood.ie can be an out-of-the-box replacement for most of Firebase's functionality as it is.