I have been placing my hyperlink at the bottom of all my websites that I have built, 156 so far. I've heard that I can be delisted from search engines if I have too many, because the sites dont relate to webdesign. Is this true?? what are other designers doing to let people know who designed the sites they create? I've noticed some designers dont have "site designed by ...." at the bottom of their work. Why not?
Having a link to your site from many non-related sites may not hurt you as long as the link text is within the topic of your site.
You could be banned, however, if you posted links to a site using non-related text. For example, a link that says "click here for more info on widgets" but takes you to a site that sells watches instead of widgets.
If you say "web design by..." in your link text, that places the topic of your site in the link and it should actually improve your rankings. Inbound links from sites of related topics would probably just have a bit more relavance to the placement.
I do the same on the websites I make and nothing happened so far.
I think that, as long as the source of your incoming links is not a link farm, p*rn website or any other crappy thing you might see on the web, you are in good shape.
If sites providing link to your site are not related to your business, yet it will carry some weightage .... may be lesser. So keep them there and increase.