I signed up in December, so I don't think it has to do with time from signup. And the site doesn't give me a timeframe, it just says I'm not allowed to post links yet.
Edit: Looks like it's working now.
I tried to post a link to my Steam community page to join the CAG Steam group, but the site said I'm not allowed to post links yet. This will be my 3rd post, so I assume it's because I don't have enough posts, but I couldn't find anywhere on the site that laid out the terms for it. If someone...