My reaction can be seen here: http://www.youtube.com/watch?v=WWaLxFIVX1s
Once a book has been published, whether by an indie press or online (both valid options!!) your road to a traditional publishing deal, should you later choose to see one, gets either a lot easier or a lot harder. Easier if you sell 10K+ copies of e- or p-book. Harder if you don't. Those sales numbers will follow you, and no, agents can't just leave out that it was previously published because that will violate the Warranties and Indemnities section of the contract you might sign with a publisher.
Further, the contracts that these authors signed would never have passed an agent's muster--one never defined which rights the publisher held, meaning that at any time they could veto anything else the book might become. It means royalty splits weren't defined. It means that you're at the pub's mercy. I couldn't take on a project tied up like that, even if it was a slam dunk.
The worst part, in one case, was that the author had been querying no time at all. Like 3 weeks or something. But she got the offer and just went ahead without an agent and, unfortunately, that impatience may have prevented her from getting a better deal.
If you don't want an agent, that's fine. But the truth is that most authors seem to say they don't want an agent, because that's in vogue, and act on that by signing with a publisher or self-pubbing. Then many decide they do want an agent. But if you've chosen to come to an agent in the middle, rather than at the beginning of your career, you're probably bringing baggage to the table.
My suspicion is that authors get that offer, and IT'S A REAL (if small!) PUBLISHER! and they just sign. Or they throw up their hands and THEY'RE GOING TO BE THE NEXT AMANDA HOCKING. And the decision may be a little rash. But by then, it's too late for an agent to get in the game.
If you get interest from a publisher, give the agents you've queried a chance to jump on you!! Tell them. Especially if it's only been a month. Because once you're published, you're published--even if it's poorly.