its because people make scripted programs to go throughout myspace functions easier (spamming programs) and that makes it so a computer cant recognize which numbers to put in, by site.
if that didnt make sense, it makes it so a human has to be at the computer, recognized the numbers/letters on the screen, and typed them in.
makes it so your program that you thought was hella tight ends right there and you have to go back to the drawing board and step your program game up
letter-verification functions like on craigslist though, the url has the actual word, so programmers can bypass it easier.
legality bullshit
for myspaces safety