For the record, they aren't necessarily
useless. I got one from work for free and got a linux kernel booting on it, based on the work by the smart guys over at toc2rta:
http://www.toc2rta.com/?q=node/2. My plan was to try to get a MythTV frontend running on it, but I got distracted before getting it done (the hardware's still in the garage somewhere, I think).
Anyway, the specs are not spectacular but they're acceptable for certain things (733MHz Celerons with 128mb RAM each); and considering how cheap you can get these devices, possibilities do exist. The site owners built a 20-head cluster for under $200, for instance -- not bad!
Not trying to sell you guys on these, just wanted to point out that someone might be able to use it.
