What are Linkbacks and other questions

[ngb1959]

I have been reading alot of boards and see linkbacks alot - is that recip link back?

Also, I was taught to put a link to your hub on the main page of your free site and I read somewhere to put a link to one of your other sites that already has a page rank. Which way is correct?

Are tgp's a waste of bandwidth?

Thanks for your help.

Nina