I've used online dating sites in the past. Since I didn't use the "free sites" there was no way I was going to invest money looking for "platonic friends". Dating sites are primarily for those who are looking for romance, causal dating, sex, or relationships. There are instances nonetheless where there is no romantic chemistry and people have been known to slip into the "friend zone". However most men don't spend money looking for friendship on these sites and most women aren't looking for friends on them either.
If one has an interest in simply forming new friendships I would highly recommend they check out (Meetup.com)
The site lists hundreds- thousands of various hobby and interest groups in local areas. The groups range from wine tasting, yoga, meditation, hiking, salsa dancing, theatre goers, book clubs, writers, professional and singles networking groups, and so forth.
The groups usually meet on average once or twice per month. It's a great way to spend time with people who share a similar interest as well as getting to know them better overtime.