[San Francisco (CNN) -- Arranging to have pizzas delivered to a stranger's door is a classic prank.
On the Web, it's charity.
Ashley Qualls found that out recently when she posted an offer on the link-sharing website called Reddit. The Santa Clarita, California, native was feeling especially charitable one day and asked the site's audience of 18.8 million visitors how she could donate to people in need.
"Someone had commented saying, 'Hey, you should take this over to Random Acts of Pizza,' " Qualls said.
Surfing to that section, she found people posting their pleas for free pizza. Members are encouraged to place orders for requests they feel especially moved by.]