I think it's all to do with perceived norms. Facebook isn't really designed to be a place for meeting people you don't fully trust - there's too much risk as you're giving them all the information you've ever shared (on facebook) ever and permitting them to clog up your newsfeed - and so anyone that breaks these norms is either a creep or a spammer.
Twitter's a bit better. I've seen that you can slowly form connections there, but only through the internet-equivalent of small talk in the magazine aisle of a supermarket you both shop at.
Back in the days of MySpace it certainly didn't seem quite as closed off - friend requests and messages from strangers because they were cute weren't always creepy (nb. may be a more a symptom of being 14 rather than an intrinsic property of the interaction...). Also, sites like Grindr seemed to have solved one aspect of the meeting strangers problem - albeit only in the gay sex niche.
Twitter's a bit better. I've seen that you can slowly form connections there, but only through the internet-equivalent of small talk in the magazine aisle of a supermarket you both shop at.
Back in the days of MySpace it certainly didn't seem quite as closed off - friend requests and messages from strangers because they were cute weren't always creepy (nb. may be a more a symptom of being 14 rather than an intrinsic property of the interaction...). Also, sites like Grindr seemed to have solved one aspect of the meeting strangers problem - albeit only in the gay sex niche.