DigitalPoint Coop is a free advertising network. You add some code on your pages and text links from other sites in the network are displayed. You also add your text links which will be displayed in the network.

It’s useful because you can get lots of one way links this way or a couple clicks. It’s main use is to increase link popularity of course. The downside is that the links aren’t static and rotate frequently.

Link-Vault attempts to solve that problem by providing “almost” static links. “almost” because if a site leaves the network, the links leave too. They have lots of cool features as adding up to 3 different anchor text for each link, choosing maximum number of links per day and more.

Both networks use a system that assigns a “weight” to each account and depending on the weight you get more links. “Weight” can depend on lots of things such as pages indexed, number of links on your pages, link popularity and more.

Both networks are worth checking out if you are looking for some more free external links and they are easy to setup. I have got numerous PR3 links and some PR4/5 already in the first week using them.

Links:
DigitalPoint Ad Coop
Link-Vault