Everything changes but really just stays the same
I was reading Clemens message about reading more books from 1973 than 2003 (http://staff.newtelligence.com/clemensv/default.aspx?date=2003-07-21). He was following up on Philip's comment http://weblogs.asp.net/prieck/posts/10359.aspx.
I have now been working in IT for nearly 20 years and what I have found is that there are very few new ideas. Microsoft has suceeded by implementing ideas that were around in the Mainframe/Minicomputer world for years but at very high cost and then implementing them on the PC platform. Take MTS and EJB you can trace back their history to IBM CICS. Also the office applications really don't do so much more than the original versions but of course they are faster and look better.
Most users like something that is familiar to them and most companies seem to think that end user training is an optional extra, stabilitity and continuity is exactly what most purchasers of the software want. That is why I think the one of the problems that Java experienced on the client is that Java applications do not look like native applications and do not work in the same way. Really it is only the home users where fashion plays a larger role and they frequently need a new look and feel.
It reminds of me when I was working on my first commercial intranet application and I asked one of the developers how many concurrent users they expected. He looked confused and said what is a concurrent user ? For me coming from a DEC Vax background which used VMS which was a timesharing system it was an obvious question to ask.
In the end learn the core IT concepts and you will find that though the names of the technology change the concepts remain valid.