No Commercial IDs

I've been getting spam comments, and I've decided to implement a policy that will help reduce those comments. A common practice among spammers is to choose comment IDs that advertise commercial products. The spammers leave general comments such as "Avoid injury when you run", and their comments include their IDs which are links to their product-sites. Therefore, all persons who visit this site are invited to leave comments about their experiences in running, walking, or cross training, but comments that include links to commercial sites (whether in their IDs or in the text of the comments) may be deleted.