I think it is possible to find friends online but I imagine the majority of people who go to those sites are looking for dating prospects. So I would mention in your ad that you are looking to make friends right now rather than romantic prospects. I did that on OKCupid and met a guy who invited me to attend a Rocky Horror show and I wish I could have gone but the timing was wrong. We chatted some and were friendly but he lived three hours away from me so we never did get together.

Where I live there is a singles group called SpeakEasy Singles. It is not a dating group but is people who just want to get together with other people to socialize. They have dances, dinners at restaurants, picnics and such. I really enjoy game night where we place cards or trivia or scrabble. There are some people there who are looking for dating prospects but most of us just want to get out of the house and have fun.