I think you can place your referral link in your signature. Just make sure to place it in a clear and honest way, maybe post a twitter and post your link there?
I don't think that's a good idea. That's still a referral spam. The rule here is that you should never reveal your referral link publicly. Even with any facebook or twitter posts
Using these methods is like shortening your link with bitly and saying look i haven't posted my referral link. its bitly link
Direct or indirect, Referral links always creates spam and bad impressions in search engines
So, never post referral link in such way that other can have access to that without taking permission with you (Direct)
If you follow rules then All Good otherwise Thread will be Deleted