Msg#: 3227318 posted 2:30 am on Feb 8, 2007 (gmt 0)
re SnapPreviewBot, I discovered that someone linking to my site on their Wordpress blog had some sort of plugin installed which popped up a window on link mouseover. This popup window contained a preview of the target web page which was generated by snap.com on-the-fly (presumably they cache the snapshot for a while).
I could see in my logs hits coming from 38.* IP addresses with the user agent "Mozilla/5.0 (compatible; SnapPreviewBot; en-US; rv:220.127.116.11) Gecko/20061206 Firefox/18.104.22.168". The page and all graphics and stylesheets were downloaded, including favicon.ico, but robots.txt wasn't requested.
So it doesn't seem to be a standard spider as far as it doesn't actively crawl a page until someone tries to view the preview image.