I've been asked quite a few times lately about the difference in the SEO benefit of a one way links, such as the links you find here on www.AdhocAds.com, and reciprocal links (2, 3 or more ways).
The reason everyone asks is that it is certainly easier to get a reciprocal link than it is to get a one way link.
The problem with two way links and three way reciprocal links is that Google's SERP ranking algorithm takes into account how many outbound links you have when they determine your PageRank, and when they determine where in the search results you will be.
That means that you want to try to build more inbound links than you have outbound links. And with 2-way and 3-way links, you have to provide an outbound link in order to gain an inbound link, so you're not really making any headway.
That's not to say they are completely worthless. I almost always exchange a link or two with any new site. But the links you get are very heavily discounted. Don't expect to move up very far in SERPs if you have nothing but reciprocal links.
What you want is one way backlinks on quality, relevant sites. Like the ones you find in our inventory at www.AdhocAds.com.