Santa Monica-based web applications provider Userplane said Thursday that it has paid out more than $500,000 in its advertising revenue sharing program, Userplane Money. The firm, which is a subsidiary of AOL, allows web publishers to include its instant messaging, web chat, and other web widgets for free on their web sites in exchange for a share of advertising revenue through those widgets. Userplane's widgets include display advertising within the software; the firm also offers its instant messaging and other applications, free of ads, to publishers for a monthly fee.