Overselling.
GoDaddy and Dreamhost are two of the most famous practitioners, but many hosts do it. Beware of it when starting a board, especially a vb board where when you've dropped $160 or so on the software only to have the board tossed off the server by the host with the phony cry of 'vbulletin uses too many resources!'
To which I honestly reply that 'It wouldn't be a problem if you were honest about your server plans.'
It's a widespread industry problem that to-date the Federal Trade Commission has done nothing about. It is, flat out, false advertising. So remember the old adage - if it sounds to good to be true, it probably is.
Here's the google search page on the topic...
http://www.google.com/search?hl=en&q...=Google+Search