They should have contest every whenever to see who grew best plants have like a 2 month period to enter, and have another one for nugs who has best one and you get rep points for winning or just recognizition.
I've a feeling they do not do such a thing for security reasons.
There have been competitions, and as far as I'm aware, so long as you talk to the site owner about it and it is deemed agreeable with their manner of operations, then you can get your own ones started.