They look for stupid users who don't realize that the girls are fake and actually find them nice and cute etc... and then they talk shit like, her doughter is dying of some horrible disease and that they need money, and for only 50$ or so you can help her lovely doughter etc....
Comfort yourself, you're not the only one who gets these annoying messages.
They seek money of one of two ways:
1- Fraud and cheating which is like the one that TomS has described earlier.
2- Promoting social services sites (match makers) which are very popular now over the web.
The second type is the most annoying as they keep sending their messages and emails from several email addresses for the same site and they have too much users doing the same. Their users work hard to send these messages to as large as possible of email addresses they can find due to the fact that they get paid per click. The more people who believe they are talking to the actual girl, the more money these people make.
The best solution I found till now is a spam assassin after spending much time training it.
Girls looking like that do not need to send friend requests - they get friend requests.
If you do not like spam on your email, you should change your email, and stop spreading it around.
I hate spam!! Because of spam I had to close down my forum
Side note @ ssthanapati:
Why close your forums just for spam?! there are 100s of ways and solutions to get rid of it. Simply, you could use the spam assassin feature on FriHost control Panel.
hate spam but what can we do but try all the possibilities to block them. i get such mails to safe someone almost everyday....
my yahoo email address is probably about 8 years old now. my new gmail account is being spam mercilessly though. hate it but what can i do. i stopped giving out my gmail address