Rules are rules but for example as far as i know posting your ref link in a post is not allowed but i have seen a LOT and i mean a lot of "giveaways" for registering under a ref link and that kind of stuff. How come thats allowed?
That's a job/task for which the OP of that particular giveaway pays. Actually that's not a giveaway as the person needs to join that website as a referral of the OP and he gets paid for the work just as the threads in Service section. I don't know why people call it a Giveaway when it's a task and yes, it's allowed as the OP is paying for the referral and making him do a job (Eg: joining a PTC site and clicking ads as his referral).
Posting your referral link just to advertise it is not allowed but if one gives an incentive, it's allowed.
@OP: Giveaway threads are allowed ONLY in the Games & Rounds section but yeah, there are certain rules as well. I guess you might be talking about Altcoin giveaways:
Most giveaway threads are no longer allowed in the Alternate cryptocurrencies sections. From now on, posting or replying to such threads could result in being banned. Existing threads will be locked.
Specifically, you are not allowed to give people any incentive to post insubstantial posts in your threads. You can't offer to pay people who post their addresses, usernames, etc. You can do giveaways off-site and link to the giveaway page in a thread, but you can't give people any bonus for replying to your thread.
Similar threads are already restricted to Games and Rounds in the non-altcoin sections, but the giveaway-related post volume is so high in the altcoin sections that I've decided to just ban them entirely here.