I use godaddy's virtual servers for one of my sites, and the traffic have been increasing a lot over time, but the site now seems to be slow. I read somewhere if you buy more ram, that would increase the speed of your site. Now is this true? (I don't know too much about this computer stuff, so please explain in a way I can understand )
Do you have access to the server itself to see how much ram is currently being used? If you have SSH shell access, type "free" (without the quotes) and paste the results here. That should give a fairly food indication of if the machine is using up all of it's available memory and swapping out to disk. Using swap space will surely slow the server down.