Search Engine Marketing - URL's From Hell - They live. Dynamic shopping and e-commerce sites that use parameters and session ID's tend to create these quite nicely. If your website has URL's riddled with percent signs, question marks, Session ID's, and at least 3 Parameters, you're clogging up your hopes for search engine success. Are you jealous because your URL's aren't as long as they could be? You can tack on as many fake parameters to the end of a real URL as you like.