Now before I really go into this, I'll detail what I normally see on FST:
If someone wants to join a site, they'll make a request and post it in the invite section.
After its posted, people will view the thread and decide whether the poster is worthy of an invite.
When they decide whether someone deserves an invite, they look at their past activity on the site. Have they been making useful posts or just spam? Have they made trades or posted in the trading section before? Have they ever had an account before, or made a request before? If you haven't noticed, one thing is missing: their BT rep.
I've rarely, if ever, seen someone judge a potential invitee by their past giveaways. Most people realize that many members are sketchy at best, and they realize people don't want to risk giving invites out on FST (not to mention many sites ban public GA's). Now that's not to say giving out invites would hurt your chances. If you lack in activity, having given out invites previously could help. I've never seen someone post on a invite request saying "You're a really good and active member of the site, but you haven't given away enough invites".
The key idea is that a BT rep of GA's isn't required.
But now turn to torrent invite communities.
I define trading as this: You are giving an invite with the intent of expecting something in return. Tracker staff ban this as it encourages invites to be given solely by the value of the invite, while ignoring the value of the member. This results in more banned members, more hit and runners, a slower site overall, and more work for the staff.
In torrent invite communities, You are giving an invite with the intent of expecting something in return.
Debate it as much as you like, but invites are almost never given out for the sole purpose of giving out invites. "Rep", along with posts, is one of crucial factors in "climbing up the ranks". Every GA has a rep requirement. If you're a 10,000 post member with no rep, you are not getting an invite. Rep is the most essential factor in acquiring an invite. Sure, you may be giving up a precious invite right now, but you are expecting great dividends. You are giving away an invite now in exchange for getting an invite later.
Take for example one thread I had seen. He was a relatively new member, probably around 1 month. I looked at his GA thread - he had SCC, GFT, the works. Oh an I forgot to mention, he had 8 SCT invites. Within a matter of days, they were ALL given out in rapid succession. He gained huge amounts of rep. He was a star in the community. Now, I know that SCT invites aren't given out for free. Once in a blue moon they may have a competition that gives out 1 or 2 invites, but this guy had 8. There was a recent 2x bonus for donations. But that still equates to paying for 4 invites, which is 50 euros. And by donating for invites you get zero upload credit. All given out, in a matter of days, to the most shady of members, collectors on invite sites. Now, you may argue that this was an act of generosity. But that is the minute exception. More than likely, it was probably a member quickly giving out invites in the hope that he would bolster his rep enough to quickly get an FTN invite (which apparently seem to be all the rage nowadays).
I ask you this: how is this different from trading? You are giving out 8 SCT invites, to total strangers that could very well get you banned from the site, not to mention that that's 50 euros in cold hard cash. You are giving out the invites, with the sole intention of expecting something in return: a high level invite because you are now a reputable member. Reputable, not from posts, activities, or past actions, but because of giving out invites. The sole principle that torrent invite communities revolve around. How is giving something and expecting something in return not trading?