Basically, a community "bands together" to create great buying power when negotiating utility prices. In most cases, the community will send out letters to all consumers and they will need to "opt out" or be converted to the plan. Using this method assures the utility company they will have the lion's share of accounts in the area and allows them to offer very aggressive pricing.
The first couple offers in my area weren't that great (I've always shopped for my own power using the tools at Ohio PUCO, had no choice with the consumption at my restaurant). Problem is (at least in my area), if you don't opt in initially, you may not receive letters for future contracts. Besides that, a lot of people think it is a scam (besides it being a bitter pill) when someone is making you opt out of something... they figure they better, or they'll get screwed. Many others simply don't trust their community govt.
I don't know why the aggregate programs aren't listed at PUCO site, my best guess is that competing companies have cried foul because they can't match the rates with such a small piece of the pie.
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