You have to be pretty careful if you elect to implement a "chat script" on a DreamHost shared server. Note the DreamHost TOS, which says in relevant part:
(bolding is mine)
Many "chat scripts" out there are very CPU intensive, and can also contribute to an overloading of concurrent connections. It my opinion that, generally speaking, most "chat scripts" that your users will "like" could well be a problem on a shared server, particularly if the like the script enough to give it heavy use.