Cheap webhosting != good.
http://www.webhostingtalk.com/showthread.php?t=474952
Dreamhost, a previously good webhost, is now overselling.
To exaplain overselling:
A little overselling is good, because it cuts costs. Basically, you are assuming that customers won't use what you allot them. If you have a server with 100 GB's of storage, and you see that most of your customers use < 1GB, but you offer 4GB's of storage, it makes more sense to let around 300-400 people to go on a server, instead of only 100. That way, it cuts costs for you and for the customers.
But, if you go overboard (Like dreamhost, and most hosts now), you run the risk of going out of buisness (1TB of bandwidth a month??? Run a linux mirror on that or something! KLForums only uses around 10GB/month, and PC Help Forum should use probably twice that, but not 1TB! Really, that is insane).
Then, if you do use up a lot of resources, some hosts (if they oversell way too much), will attempt to kick you off of the server. If they are overselling mildly, they can afford to move you to another server.