AOL does not really have spiders. What they have a proxy agents. The way it works is they download the page for users.
Let's say you are using AOL for an ISP service. You want to view this very page. You click on on your WebmasterWorld bookmark. AOL then sends out a 'spider' or proxy agent to download the page. AOL then serves the user that page. The next time somebody else wants the page, aol just gives them the copy out of it's cache and not connection is made.
In order to serve all the possible combinations of a site, AOL must change the user agent string of its proxy spiders/agents. You can sometimes get 10-20 hits from AOL 'spiders' (they have spider in their domain name) in rapid fire succession.
Try the AOL Webmaster FAQ [webmaster.aol.com] for more information (IE only I think). Look at the Proxy and Cache items on the left menu.