What is a Blob Vault? The Blob Vault is a part of the Ripple project.
What is it?

The project should get a reamdme.
The "blob vault" is a very simple encrypted storage system used to store Ripple wallets. Your Ripple wallet stores your annotations, named accounts, and so on. You can create a new wallet with the same secret and get your funds back, so losing your wallet does not mean losing your funds.

The guts consist entirely of about 100 lines of Javascript.