This post stems from an article suggesting The Gruen Transfer had received over 6,100 user generated submissions on their website. As of the end of the season tonight, I've read it's reached 10,000. If this is true, the guys behind it must be ecstatic.
The question I feel most important here; What is the purpose of user generated content? I'm going to go ahead and suggest the answer would be the interaction with the brand. Or at least should be. If you're going in looking for free advertising you're doing it for the wrong reasons.
The user generated content on The Gruen Transfer's website follows a template. This template allows users to easily make an advertisement in five minutes or so. This is great because it allows the low involvement users to get involved and also means 10,000 entries. A similar concept has been used for Design A Coke.
But this limits the user's creativity. As a result you have 10,000 entries that all look the same and because of that most of them are only viewed a couple of times at most. Most importantly the interaction with the brand is limited. Whilst I understand you need different levels of entry for interaction, I'd much prefer a passionate user who spends two hours interacting with my brand than fifty people who spent five minutes.
A passionate user is likely to then upload it to YouTube. Then they're more likely to send it to their friends. Then they're more likely to check back on it regularly. They're also more likely to create something remarkable not restricted to a template.
Essentially, as with most things, it comes back to Seth Godin's idea of "who" instead of "how many"....