If you are talking about the sites in your signature, you most probably can get hurt, because you have site wide irrelevant to your site theme links:

Web Site Design, Search Engine Optimization, Optimized Video Services and Content Management System
by Foster Web Marketing

If you would add to those links the nofollow attribute, then you should not have a problem?

Which Professional and Ethical SEO would ask a customer to do that? Very strange...

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