I've been on plentyoffish dating site for 9 months. My reply rate to messages sent to female strangers is pretty sad; something like 1/80 bother to reply back. Seems like a waste of time typing long interesting msg's to send to these ladies, so I eased off using it and thinking about deleting the account. I might get 1 email every 2 months from a complete female stranger (somebody who msg me first), but they are always not my type, physically they are always the big 200lbs women.
Out of curiosity to discover whether "am I ugly?" I created a false account with photos of a big, hunky handsome fireman type. I got 16 emails in the first 48hrs from female strangers, so it proves the agenda of these women. I actually got carried away using it, lots of girls gave me their personal mobile phone numbers after just a few replies.