I saw many webdesigner companies adding a small signature on each website they make. Signature could be masked by words like credits, design by..., but they all contain a direct link to the webdesign company that made the website.
This can be obviously good to drive more traffic to the webdesign company by direct visitors that might click on 'credits'/'design by...' link.
But what about SEO:
Is it good for Google? (Or is it seen as spamming bad SEO technique)
It should increase the webdesign company's website Google PR, shouldn't it?! And in some way push the wbsite up on Google search results? *
NOTE: obviously I'm supposing the webdesign company's website is also a site with interesting and decent contents, not just an empty idious site, I know Ggoogle looks 1st for contents, but besides that...