In general search engines are able to identify keywords in the URL even if they are i.e. a parameter that follows a "?" or other non-alphanumeric character. They might not treat it as an equally strong signal as when the keyword is a part of the file name, subdomain or domain name though. Hope that answers your question.
Building Links That Matter
9/27/2010 Have you ever finished a large link-building project and have been disappointed by the results? Did you ever feel the links you got weren’t working? Well, you’re not alone. The primary reason I’ve found people run into a link problem like this, is that they fail to understand that it’s not only that links matter, but that not all links matter equally. Sure, every...