The key here is to see it from the opposite end -- from the potential employer point of view. We (I am a programmer, but I do a lot of interviewing and general recruity stuff) get metric raftloads of resumes, interest emails, and so on. Most of them are pretty unexceptional to begin with, and most candidates also lie^w exaggerate.
In order to find the people you want to hire you have to trim down the ones you talk to by some means. Think of it is a heuristic based search -- it won't be perfect, but it can be very good. You take the traits which correlate highest with success (I will leave success nebulous on purpose, that is a whole other discussion) and start whittling down the search space. A college degree tends to correlate highly with being a good or great programmer, therefore it is frequently used. This is a simplification, of course (though I am sure there are shops which really do this), but there it is.
In order to find the people you want to hire you have to trim down the ones you talk to by some means. Think of it is a heuristic based search -- it won't be perfect, but it can be very good. You take the traits which correlate highest with success (I will leave success nebulous on purpose, that is a whole other discussion) and start whittling down the search space. A college degree tends to correlate highly with being a good or great programmer, therefore it is frequently used. This is a simplification, of course (though I am sure there are shops which really do this), but there it is.