NoOb, a website/forum makes organizing a clan and getting to know members a lot easier. Setting up a free forum shouldn't be terribly time consuming. You can look at HyPE's site [http://hypeclan.hypeforum.net] as an example, and on HyPE's homepage there is a list of links to other clans' sites.
That said, if you don't want to, you don't need a site, but a clan that exists solely in-game won't be as fun with random people seeing your post and joining. If you want a site-less clan, I think it might be more fun if you set it up with people you've played with frequently and gotten to know in-game. But if you want to have some sort of recruitment process, I suggest a site.
Hope that helps, and gl hf with your clan,
HyPE|GDM
That said, if you don't want to, you don't need a site, but a clan that exists solely in-game won't be as fun with random people seeing your post and joining. If you want a site-less clan, I think it might be more fun if you set it up with people you've played with frequently and gotten to know in-game. But if you want to have some sort of recruitment process, I suggest a site.
Hope that helps, and gl hf with your clan,
HyPE|GDM