The web is the web is the web.
If you can connect to the web, you can go to any site you wish, as long as your ISP does not block them (don't know of any that do such a thing).
Using your mobile phone as a modem shouldn't be stopping you going to anywhere as far as I'm aware (though it can be expensive).
A chat room is only a website - just like any other website.
I really don't understand what problem you're having.