This is known as SSO single-sign-on and is a known issue and ppl are working on it! There is a bug open at the bugtracker and many threads in TMO so please feel free to search for it for further information on the process.

you need to sign up for talk, garage and bugtracker that's all!
the talk account is just for talk and the garage account is for all the rest but bugtracker (afaik). the garage account transfer to wiki and download and so on does take a while. So please be patient with the sites to update your user data.

closed.