Web 2.0 URL keeps getting banned from Blog Comments. Any advise?

I been using all my web 2.0 URL profiles to leave on blog comments. But after a while they all get banned. I don't spam them I manually add them. I usually do about 1-2 comment a week. After a few weeks the url gets banned. I mix the anchor text with my name and target keyword. Please any advise would be greatly appreciated.