I thought I'd give this a serious answer.
I don't think much has changed with regards the rules on this issue since the last time it was brought up. In this single thread it's "acceptable" in the loosest possible sense at the moment.
I think most of us understand that when people are using the term we are using it in jest or as an exclamation of dismay, much in the same way people would say "Shit!" or "Fuck!" if they stubbed their toe on a bit of furniture or your central defender scored an own goal. That's just the way the word is increasingly being used, particularly in British society and football communities, by adolescents and young adults these days and the majority of us currently in here fill one of these groups.
With all that said there are some things to consider. This is a worldwide forum with a diverse range of members. As such the spectrum of acceptability on the use of this term is also equally large.
If you're having a dispute with another poster calling them this word is generally not a good idea. You may think "it's fine because I'm saying it in the football thread", "I meant it as a joke" or "it was just some banter" but they may not react in the way you thought they would. Don't always assume that using the word is fine and that you're immune from any reprisals.
I'd hate for the number of contributors to this thread to be less than what it could be because of our prevalence for using this one word. If it was becoming clear that this one issue was causing new people to the thread from taking part and joining our community here I think the leniency the football thread has on this issue would likely change as a result.
I think you guys are wise enough to know when it is acceptable, when it isn't and when someone has gone too far. For instance excessive use just for the sake of saying it isn't cool.
Finally a reminder, using this word anywhere else on the forum will get you zapped straight away so just don't use it. This holds true for all football/soccer related threads which may open up in OT. For example using it in a World Cup thread lead to a ban.