A featured WebmasterWorld thread has tips on what things to look for when purchasing links. I thought I pull out 10 of them to make a top ten list:
- Relevancy to your page
- Alexa ranking
- Site popularity in niche
- Site health in search engines
- Location of links on page
- Site rankings
- Do they look bought?
- Are your links useful?
- Number of other links on that page
The list is in no order, just some highlights from the WebmasterWorld thread.