http://ashitaka-san.home.comcast.net/yayrant/ieharmful.htmlsnip
Internet Explorer keeps an archive of all of the websites you have visited. This archive is
completely invisible and cannot be deleted by any normal means. If you thought you could get rid of it by clearing your history or deleting your cache, you are wrong. It is kept in a folder which is segregated from the main filesystem, but it is there!
...
Internet Explorer is prone to many vulnerabilities which are much more frightening, allowing hackers to launch files on your system or transfer your files to their hard drive. It is proof enough that Windows XP comes with an "auto-update" program so that its users can download and fix vulnerabilities as Microsoft gets around to them. Note also that Internet Explorer goes through entire "service pack"s in order to close large numbers of security holes.
/snip
I just found this the other night and I thought you all would like to read.