Meeting people is an easy thing in primary school... your friends are those living on your block... playing man hunt and stoop ball - then the kids at school - then the kids in CCD - and of course the kids in your sports programs... you met tons of girls and boys with similar and dissimilar interests... you grow.
In HS it's still pretty easy... now you open your doors to your classmates, those on the same bus route, those on your sports teams, and those in brother or sister schools - and now you can also add friends of friends... a whole new word.
In College you still had all of the previous opportunities to meet people, and your class is in the thousands rather than the hundreds... you can meet people in your dorms, in your classes, in your campus, i the library, etc... but in addition you were more mobile - you could afford to have friends a little further away. Also you can join groups sponsored by the school... and you had the opportunity to meet people through work and internships.
As a young professional in a young work environment, I still meet many people, unfortunately, few have the same passions.
I love to snowboard... but I don't know many females who do... or even people of either gender who are at a similar level. It seems I've hit a plateau on my accelerated snowboard learning curve and need a buddy to push me over that hump.
I love to create ... to sew, garden, build - but I don't always have the means or the help. It would be nice to know someone with similar interests to throw ideas at and to help guide me along the way.
I now love to kayak... I really fell head over heels - I think it's an awesome sport... just under snowboarding. I don't know a single person who kayaks... let alone a sit inside white water kayak or play boat which is what I'm interested... might as well go extreme! It would be nice to have someone to learn with... or even if they already knew how... someone to paddle with once I learn a bit more and can feel comfortable outside of a instruction setting.
Those are the thing mediums like facebook might be good for. It would allow you to post to the masses looking for interested parties. Maybe even someone to try a new sport with. Unfortunately the lessons and tickets to many of these sports are expensive... so it's a big decision to make, but I'm all for it!