setting up a forum to "pump up" ranking position?

I have a dynamic website - all content depends on users. As you can guess, it's not ranked well. I want to change that by adding a "phpBB" forum to my site.

Is that a good idea? Can i somehow use existing uname/pass pairs from my database so site users can login to forum with same c开发者_运维知识库redentials?

The more unique content the better. You should try and get some inbound links too though. You might be able to migrate existing users to the phpbb system. Depends how you have your current users setup. Install it, create an account and see if it matches up in the database with your current system. Are you storing the passwords in plaintext? If you are then it should be trivial to move the users (but you really shouldn't be doing storing them in plain text, thats another post though). If you are storing md5 hashes, then you'll have to see if phpbb is using the same hashing scheme as you. If not, then you'll have to get users to sign up. Or you could hack phpbb to get their authentication system working with yours and just skip theirs altogether.