There are always exceptions to that particular part of the forum rules.
I can recall searching and reading through about this in the past because it’s very common to see referral links on ANN threads of casinos, and campaign managers can also share such links.
https://bitcointalk.org/index.php?topic=5172343.msg52557780#msg52557780In the thread above where 1miau discusses the ref link, there were exceptions pointed out.
I know it is against the rules to post referral links only.
-snip-
Correct,
but it's allowed if it isn't spam.
The only exception is if you're the owner or representative of the gambling website
and you're posting it as the official thread of your casino, that's normally tolerated because it isn't ref code spamming.
Example:
wetsuit's thread - with "
?r=4" as his ref link.
However,
the description of your "review" is one of the example of ref link spam.
Technically they're against the rules, but people kinda started to get a free pass in the Gambling Discussion sub a while back. Personally, I don't really care about them regarding users like tipsters who are giving their picks away for free and include a ref link if anyone wants to put the bet through them. At least they're putting some effort or at least thought into their posts, but I'm sure many others (including mods) would disagree. If someone just signs up to post a ref link though that would be a different story. Theymos will probably say take them on a case by case basis but I'm sure everyone has a different opinion on in what context they should or shouldn't be allowed (especially regarding tipsters).
Edit: From the conclusion which I can grab from the whole thing, the rules are to prevent spamming or, in the name of promoting referral links, if it's added in a well-detailed discussion, it won't be considered as spam, especially when there is a sense to what's being discussed there and not just a referral link that's being shared, and each moderator is left with the decision to decide if the post with the referral link is regarded as spam or if it's worth considering.