What is Distance Learning? Can it Help Me Find a Better Job?

I’ve been hearing from a couple friends lately that they’re thinking of going back to school to earn their degrees. I was kind of surprised, because both of these guys aren’t really the “college type,” if you know what I mean. So when I kind of pressed them about it, they said they were doing it all online. That kind of sounded like a scam to me, like they were going to get some kind of fake diploma or something. So I did a little investigating of my own.  Turns out I knew a lot less than I thought. But I still don’t really get the concept of it. Can someone tell me what is distance learning? Does it have to be done all online, or can you do it like those old-fashioned “correspondence courses?” And then, of course, what does it get you? Would a distance learning degree be as good as a degree from a regular school?