I've been using LinkMetro Pro for over a year and my site is at Number 4 on Google with over 640 million other results. It's very useful so long as you: 1. Check where your link has been placed 2. Make sure your link can be reached from the other site's Home page. 3. You don't accept links from PR 0 sites (they should write a few articles to get a Page Rank before asking for a link!). 4. You accept links only from sites relevant to yours. 5. Your links are in a category structured directory, and not number 1425 of 1500 links! 6. You use the LinkMetro feature provided to regularly check that the backlink is live. Due to Google's PR calculation, any reciprocal link with a PR>0 is worthwhile, and in any case I get a lot of traffic from my links. One point on 3-way links: If these are designed to confuse Google's PR calculation, Google can detect them and will penalize them. You might get away with it for while and then your webpage might disappear from Google's listings. I never accept 3-way links. I cannot comment on any of the other link exchanges mentioned in this thread since I have never had to use anything but LinkMetro, but I have used it properly to the above rules.
If you liked link metro but don't want to pay for the advanced membership, I'm giving the upgrades for free: http://www.link-exchangers.com
www.linkwizard.net update our system. Functions available: - exchange links - sell links - buy links Linkwizard a Google-style!!!
Link-Exchangers.com is functionally superior to linkmetro.com. It is based on the same programming however it has many enhancements such as the ability to email webmasters of broken links with a single click. One way links will be available inside the directory very soon, and the program currently allows one way links outside the site through the script. You'll be able to buy and sell one way links. The only thing it doesn't have it thousands of members but it will get this soon too. Upgrade to the advanced features is free right now, (as in LIFETIME free membership) and any donations go 100% to marketing. Lets get those sites registered. :>