When compiling forum targets, how to know if the signature forum links and profile links are crawlable (not just viewed by forum members)?
If you can access the url for the page where your link is without the browser redirecting you to a login page then they are externally viewable by search engines
There is very simple method. Check the Google cached snapshot of the page which are need to be checked about the signature reading. If signature is visible there, then its means that Google is crawling the signature of that forum.
I think you can check your profile stat & even you can check ur back link profile ( you may have some referral traffic )
This is correct answer; but after reading your question twice, do you asking no follow vs do follow forum link?