I don't know if it's a commonly shared experience or not, but I love ebay. It's like a yard sale, except it's somehow been magically connected to a search engine invented by your geeky cousin.
Say you've lost the little wagon that comes with the Fisher Price Little People Farm and it bugs you a lot that there's no way to get the hay into the barn without it. You type in some search involving "little people" and "hay wagon" and there it is, the wagon you need is living in the house of a lady in Oklahoma whose children have left home and she's finally decided it's time for the hay wagon to go to the good home of some aspiring farmer. She absolutely doesn't care that you live in a blue state — she knows that the desire to get the crops in lies in the hearts of all American children. So she sells it to you for $1.99 plus postage (not inflated postage either, because that doesn't sit well with her.)
And then the best part is that about a week later you get a real, honest to god package, and it smells like and looks like a real person sent it and there's your wagon and the crops can now be harvested.
Ebay is my connection to the rest of the country — I love the different ways people figure out to mail things, the notes they send, the stuff they have hung onto and the magical fact that the thing they don't need any more will do very nicely for you and yours.