What is paid bid directory?

Ive some ppl paying for links at paid bid directory?
Whats dat exactly for?
Doesn't it easier if i submit to more free directories to get backlink?
why should i pay?

I've read that you basically are buying links but i don't know much about it.
Here is a nice site: check some of their categories.

Bidding directories are just a spin off on normal paid directories, typically they earn a little more than the one off fee directories, hence their popularity before Google nuked directories, making most useless.

Free directories offer no real link value to be honest, apart from a select few which are very difficult to get listed at, I would advise you don't bother submitting to thousands of free directories, only top quality ones. Most paid/bidding directories have usually been dropped by Google, except a few quality ones such as business.com and Yahoo's directory.

Summary: Only submit to the best free directories, although their is also controversy over their value as well, but I don't want to write pages about it, and ignore paid directories unless you have a lot of money spare, then Yahoo dir and so on.

From what I've seen, the bidding ones are like PR6/7 and you are bidding for a front-page link. As Bacanze has said, it's pretty useless now.

If i spam using Xrumer? isn it betta though =D