At the time of the old forum, there were a few problems with piracy. Kids who'd just downloaded to latest freebie to make its way to the torrent sites, without having the faintest clue of engine's capabilities or requirements (in terms of both hardware, effort). When you ask more sensible questions like yours, most members are more than prepared to help if they are able to, without you needing to get your wallet out,
Since moving to this new forum about 1 and a half years ago the piracy pretty much died outright
Well yes, donations are a great way of showing gratitude, but personally I wouldn't offer them upfront (maybe that's just me). To be offered a donation afterwards without any indication in advance really makes you feel like you've gone the extra mile to help someone.
But to have been offered it upfront: let's just assume it's me your offering to pay for a tutorial. I go away and write one that actually doesn't really help you at all. Now what do you do? Do you pay me anyway to avoid upsetting me over the hard work I've put in and think to yourself "I'm not asking her again", or do you honestly admit that it didn't help, and thus not pay?
So I'm not saying don't reward people who have helped you, but just be aware of some possible implications of it. And since we're like a big family here, help is normally offered for free, but no one's actually going to say "you must not pay me"... It's like paying your sister to iron your suit for you - you can, but she's probably willing to do it for free.