To lend another opinion -
Yes, the Staff and Mods are well aware of the difficulties involved in fairly enforcing a commercial policy.
As Bill mentioned, don't think the coral fraggers "get away" with it all and fish breeders are picked on. We actually enforce the same rules on both. The difficultly lies in determining when someone has "crossed the line" from hobby to commercial. Many of today's best-known online shops started out in a garage as a "hobby."
So, when did they cross over into commercial? For us, it's all about trying to determine intent. It's not about breaking even, just recouping your costs, or making money. It's about creating something with the specific intent that it be sold. Whether it's putting together a LED lighting board, doing mods on maxijets, fragging corals and growing them out, or breeding fish, if it's being done with the intent to distribute them here, then that's commercial.
Okay, how does one determine "intent?" We don't have a crystal ball or mind-reading powers, so we have to really judge things objectively. People who have "too many" of a certain coral, or too many varieties (especially if the variety is ever changing), people who offer to "get something" if someone doesn't see what they like are pretty obvious. People who set up websites to take orders, accept credit cards, create email and waiting lists for their corals also are pretty cut and dry. Ordering a lot (or many) of one thing with the intent to sell some of it to recoup costs is also prohibited (why was the extra purchased - to sell here, so it's commercial). As is collecting livestock to sell.
But some areas of "intent" are more difficult. Selling a few fish the first time you breed them wouldn't be commercial. But what about the second time, or the third. When does it stop being a "can I do it" experiment, and become a "hey, I can make a little extra money on this?" It's a grey area, and one we struggle with daily. We are always willing to have discussions in this area (provided they are polite), but once we have made a decision (as a group, we don't make decisions in a vacuum), the member needs to respect that decision (if they don't, that's when loss of posting privileges rears its ugly head).
And nearly every person we identify as commercial claims to have only the best interests of the hobby and other hobbyists at heart. Hey, they're only trying to get a good deal for their fellow saltwater geeks, what could possibly be wrong with that? Again, it's not the price, nor the balance sheet (making money versus not) that makes it commercial - it's the intent.
So, back to intent - dedicated grow out systems, multiple frags and frag racks help establish this intent with the coral crowd. It's not just pruning your corals and letting them attach on a piece of live rock, it's usually multiple frag plugs on eggcrate in a dedicated system.
For breeders, it's not just having a larval rearing tank. We realize you're going to have to have a dedicated tank, as well as phyto and rotifer set ups (BTW, we've identified some folks as commercial because they suddenly realized they could make money rearing phyto and/or rotifers and selling them regularly here... again, the intent changed from raising for themselves to raising with the intent to sell). With breeders, it really comes down to the time and energy you've already invested, and the amount of success you've already had. If you've tried 5 times to rear clown fry, and only had a few fry live, we probably won't consider you commercial. On the other hand, if you've been successful several times and still want to sell the fry here, we'll probably shut you down (by now, you should have a local outlet for your fish).
We have sponsors that do EXACTLY what some "hobbyists" do with regard to fish breeding and sales and coral fragging and sales, and yet we do not allow them to advertise or sell outside their banner or dedicated forum. They're paying the money that keeps RC running. We have to have some type of mechanism for identifying those hobbyists who have crossed over into the commercial realm (you'd be surprised at the number of hobbyists we've identified as "commercial," who fought and argued about it, and yet later opened e-tail, and sometimes brick and mortar, businesses).
Our system isn't perfect, and we welcome real suggestions on improving it. Just don't expect a pass for all breeders, nor a pass for all fraggers ("hey, I keep a tank, I'm a hobbyist" just doesn't make it as an excuse).
In any case, I hope this helps explain some of the criteria we use. I emphasize "some," because some of our most commercial posters also seem to want to argue every little comma and period, looking for loopholes and demanding their "right" to sell on RC (no, really, you'd be surprised at some of the exchanges we have behind the scenes with people).
Kevin
) I know what Matt's feeling right about now. 
).
