I think both are interchangeable and mean pretty much the same thing, both can cover the same multitude of the sins. I would say the difference is that 'computer programmer' was a term which was must more common in the 80's and early nineties, a time when computer fluency was much less common, As such had a lot of negative connotations, images of spectacled geeks sitting in the computer room during their lunchtimes playing on their php while the cool kids played sports in the playground. 'Software Developer' I'd say came into vogue more during the late 90's and 2000's, around the same time that the Internet started to take off. A time when those 'geeks' where becoming billionaires (on paper anyway). And I think this has continued through to today, especially when everyone is fairly computer literate nowadays and becoming a developer is seen as a valid path to stability, success and riches, Basically I'd say they're the same thing. But girls take 'developers' to their high school prom (metaphorically), whereas as popular girls definitely don't date 'programmers' :-)