I use to be part of a community that did that. People voted daily to get ingame cash, only raising that server on the list higher.
Alot of listing websites can work through a plugin called
votifier. It allows the webpage to contact the server(If I recall correctly its a special listening port) and it completes any command(s) configured in the .yml file.
The config file can be more advanced aswell, as you get $500 ingame for voting on abcxyz web list and only 200 when voting on 123789 web list. Other then money, you can do any command out there.