You could try SGPlus. It integrates Facebook and Twitter into Google+.

You could try SGPlus. It embeds both Facebook and Twitter into the Google+ interface.

Collatz conjecture. Beat that!

IMHO, the most important feature of SpiderOak is zero-knowledge. No kind of information can be recovered without knowing your password (at least theoretically). DropBox promises AES encryption, but the keys are actually on the server, and you can notice that by uploading a big file which is already on the server, but on someone else's account (e.g. an Ubuntu ISO): the upload will be almost instantaneous. With SpiderOak this doesn't happen, since your files are encrypted before the upload with your master key (which is itself encrypted with your password).