The Japanese (I have read) have developed a device on which you register various salient characteristics of yourself and your desired companions. When you get near someone with another such device and they find you compatible, you both get beeps.

In a commune I used to belong to, there was a game called 4-point. If you wanted to play, you went down a list of the members and gave everyone a number from 0 to 3. The manager then compared lists and put in your mailbox a list of all the members whose rating of you and your rating of whom added up to 4 or more. You took it from there, without fear of rejection.