That being said, premium POF members can set a filter allowing only people who also have a paid membership to message them.
Unlike other free sites, basic features like messaging your Mutual Matches don’t require an upgraded membership. The sheer number of users makes it a great option if you live in a rural area or small city. 
You'll find daters looking for just about everything, from a long-term relationship to a hookup. Markus Frind created it way back in 2003.
It's also one of the oldest dating sites out there. Patti Stanger, the Millionaire Matchmaker of Bravo Network fame, met her long-term boyfriend on the site.
It has a huge user pool, with an enormous variety of singles - including the occasional (okay, very occasional) reality TV star.