Here’s an interesting concept. I almost wish that I had thought of it. Send these people your stories and they make them available for anthologies. A person who likes short stories can pick and choose from a bunch of stories and create a customized anthology. I would guess that the anthologies are published through LuLu, which means that there is a manual step for each anthology sold so you have to rely on a human to format the stories, select the cover and set up the book with LuLu.com.
I am tempted to send them 20 or so of my published stories. You make in the neighborhood of a dime for each anthology sold.
The reality of the situation is that not many people read short story anthologies. I think they will be lucky to sell 100 anthologies a year. I hope that I am wrong and they sell many thousands. There are a great many excellent short story anthologies available and if these don’t sell all that well, how can they expect the roll-your-own anthologies to sell any better?
Another drawback is that LuLu.com is already too expensive. These people will slap their own profit in addition to the $1.50 for the author’s share.
Author’s are paid after their account reaches $20, which is about 150 to 200 anthology sales. My opinion is that you’ll have to wait about 5 years before you are paid.