Facebook, it's really good for finding people who share your hobbies and are passionate about something. It's a pretty good way to learn things too, like, what are the cars in an old family photo album. This comes up often

someone posted 6 photos from their great grandma's photo album to the Art Deco Era Motor and Fashion group, and asked if anyone could identify them. It worked. 

https://www.facebook.com/groups/712743252141034/permalink/4026598270755499