Almost none of them really know what they are talking about, but they are using a lot of "important" sounding words - but from how they use them, someone who actually understands those words knows immediately that they don't know shit.
I really love it when I hear those people talk about how experienced they are, because they got their Windows XP machine to recognize their foto camera, and stuff like that.
Topics those people are REALLY interested in - and "of course" are absolute professionals in are mainly:
Digital fotography, Skype, downloading MP3s and Videos, burning DVDs and thus they are sooooo cool and of course professionals.

Currently I just had an "interesting" talk with someone like that and I'm still emotinally too involved - so I think I'll finish this post some other day.