Perhaps you run a blog or you planning to have one up. You want more and more comment to build some links. Right? Everyone want. But the problem begins when you leave open comment section to everyone, so anyone can come and write a comment. Normally people start spamming. This trend i have seen across all websites on Internet. So if you want to get some quality links moderate every comment. Be honest to yourself. Publish a comment if its worth else do away with it. A bad quality link or content on your site is like a parasite. Keep your blog clean of spams. Nobody likes those unwanted threads. To say a no is better than yes.