IF you're actively punting and seeing girls based off reviews or intel found here and you aren't reviewing or commenting constructively you're not being useful. It doesn't matter about how many punts you do as any actionable intel is useful. Sure you're "more" useful if you can offer more info to other punters that they might make informed decisions at lower risk to their VFM tally.
If you're irrational or unobjective then you diminish your contribution because the rest of us are left guessing as to how sound your judgement is.
If you encourage SPs to behave poorly or alter their service offering and pricing to the detriment of other punters then you're scum.
If you're withholding current useful information then you're not being useful, other successive punters may be losing time and money as a result. Any time you "TOFTT" and it turned to shit, if that SP had been listed for even a few days it's likely that a UKP user (given the site's popularity) had already tried and failed with her, sure you should warn us but someone should have warned you before! Silence about bad SP experiences has no utility, no cameraderie, no respect for those who've contributed to the benefit of others. Condoning bad service or poor VFM is almost as bad as encouraging it.
If you encourage SPs to improve their service (skills, quality and consistency) then you're a champ.
If you convince SPs to drop their pricing or offer better deals you're a fucking legend.
I agree with most of this particularly the scum comment, punters who advise WGs to raise their prices are totally selfish scum in my book. What sometimes occurs is the deal is the punter stays on the WGs old rate while taking his advice other punters have to pay her new higher price. And the irony is I know of a few occasions when the WG did take the punters advice and increase her prices but she didn't keep him on the old rate. So the outcome was a selfish scumbag just helped ensure punters would have to pay more due to his big mouth.
With negative reviews the longer you don't post them the more punters may be getting the same off the WG, so get them up asap. And its of limited use posting on another punters negative review that you received the same if you have been a member a while, why didn't you review it to warn other punters.
With positive reviews I have fucked myself on occasion when the WG I gave a positive review to puts her prices up and becomes impossible to book as suits me. This happened with Ameera among many others. So I may now wait until I have had my fill before reviewing then the above makes no odds to me. I do still review positively quicker than that sometimes, and if I am not going to punt with the WG again no problem doing a positive.
A useful poster on here is one I find credible as a punter. If they do reviews all the better. UKP exists only if punters post, so many make hardly any contribution let alone do any reviews. They turn up out of the blue and get the hump if someone dares question their credibility,

so contribute and that is less likely to occur.
I read on occasion that posters are too busy to do reviews, what a crock of shit, unless you are a slave you must be able to find time, at least sometimes, it only has to take a few minutes to post a review up, they don't HAVE to be long.