What we need:
- People who're good at coding browser plugins (you)
- A Database
I would write a plugin by my own, but I've no idea how browser plugins work right now and I'm generally lazy about learning new programming languages or however you wanna call it. Moreover: you have currently plenty of users who would populate the database.
This has been suggested and discussed in the past, and has always been rejected.
It's more of a plugin thing than a main BBLog feature, that is of course if a plugin developer wants to host their own database.