Add nofollow to all links in posts

There are a lot of people spamming here, trying to build links and it's working due to TalkFreelancing not having the nofollow attributes in the links posted by users.

Bottom line is, this place shouldn't be used to build linkbacks for search engines! Fake signatures, signatures with keywords to various sites while the poster is responding to others/making new threads that aren't contributing or making much sense.

Surely this will improve the quality a bit here?