I always hear that session id’s are bad for SEO. But most do not take the time to explain why the engines have such problems.

Search engines are giant databases that store content that it collects from the web. The key that each engine uses to identify a page is the URL, now imagine a URL that looks like this. http://www.aaronshear.com/coolnewpage.php?session-id=123456

Google comes by the site and picks up the URL, and processes it. After a day or so it goes back to the page that contained the link to this cool new page. The link is suddenly different; it now looks like http://www.aaronshear.com/coolnewpage.php?session-id=1234567, now Google has to store this page as a different page. It looks like a dupe from the earlier page so it blows it out. Google then try’s to crawl the old page and get’s an error message ‘Your session has expired”, instead of seeing new content.

On top of the fundamental problems with session id’s, imagine you write a great article about basketball. It’s perfect in every way and people love it, so they start linking to it. Instead of them linking to one page, now they are linking to the page with the session id that was assigned to their visit. Now all of the links are going to separate pages instead of just one. If you want to get a page to rank, you need links.

Here is a random Rant for the day.

I love how SEO’s say you are confusing the spider. Ok this is a pet peeve on mine, how do you confuse a spider? You cannot confuse a computer it does what it’s told. Nothing more, nothing less.