Of course, security considerations prevent you from importing a user's bookmark file into your website, (if that was what you wanted to do?)
That information is only available with full system priveleges - the user might not want everyone to know what they have bookmarked!
Technically this should be possible, with the user's permission, by using an .hta to read the bookmark using system-level .js (fso etc,) and some brute force parsing on the server, but I can't imagine many peeps allowing the .hta in!
Regards,
Alex