At various points GBAtemp has had subdomains* (ftp, download/news, cheats which was a whole other forum, irc, irc2,.... and the usual email related ones). I imagine you found a link somewhere that used that domain at one point, I forget what WS was (don't think it was the old workspace but could be wrong). Today for simplicity and ease of doing SSL (the cheaper/free providers of certificates limit your subdomains or require you to separately maintain each one) most of those are not so and will redirect to the main forums after a fashion*.
*people tend not to make as much use of subdomains as they once did but it was a nicer way to have multiple websites on a single domain, as well as isolate things fairly effectively and the other stuff mentioned about maintenance. Typical use was businesses, schools and governments using them for separate departments. With modern web servers, the cheapness of domains, the reduction in prominence of non web traffic (connected as a general user or member of the public to much FTP on the web for any kind of big or notable entity lately?) and people seemingly accepting someurl.com/department1 as being just as valid as department1.someurl.com it kind of fell by the wayside.
**wildcard redirect of subdomains is tricky so it might just be the plain url and no subdirectories it might have had.
If it is a subdomain you should be OK, however certain things might be hardcoded to use one or another subdomain, or not use a subdomain so you might find functionality broken somewhere along the line.