Here's something I wanted to post here, an article about "pickers". In this case it was a Barbie picker. He calls himself a "garage sale swindler" because he buys unopened Barbies and sells them online. It's here
How is it related? Because he's taking his time and energy to know the market, to search diligently for the deals, and then to make them available to people who collect. Yet, he feels the need to explain himself as a "swindler," I guess because he knows more about the value of something than the seller does. Maybe he thinks he's taking advantage of people (and maybe he is).
In any case, I think part of the controversy about the Craigslist thread is related to the fact that ebay and craigslist and other outlets have taken away the advantage that someone might have from combing their local sales and flea markets. When I grew up, most of the nice things I owned came from a yard sale or the equivalent booth at a flea market or from trading with other folks (that, or I made it). Not the clothes on my back, but I knew plenty of people for whom that was true, too. That was the lifestyle we got to live - if you wanted something other than what you had, you earned enough and then dickered for it. Or you "picked" things to horse-trade. You bought things at pawn shops or second-hand stores or damaged freight stores, and thrift shops (only in the bigger towns back then) were a special treat. Did we ever "know" the value of something? Nope. But usually we bought things based on their value to US. If we bought things we would use, it was because we knew we could benefit from using it. If we bought something to barter, it had to be relatively stable in value and well understood and evaluated easily.
Now that there's an Internet it's so much easier to figure out values because of boards like CN and others. And it's easier to find an audience of people who want to buy something or sell something. Remember the Starry Messenger? That was the Wild West compared to now.
So if our CL thread makes it harder to get something for nothing, that's unfortunate. I'd rather see sellers get fairly compensated so there will be more sellers, and then there will be more buyers, and so on. That's how a market works. It's a beautiful thing.