I haven't done much web development now for 7 years. I did a large-ish project at work using AxKit (probably one of the highest traffic mod_perl applications in existance, doing about 200 million transactions/day) about 4 or 5 years ago, but I don't really count that as it didn't expand my knowledge of web technology in any way.
I keep reading about new web "stuff" - Rails, Django, Seaside, etc. None of it really interests me all that much because frankly the core of the web doesn't appear to have changed a whole lot to me - you do a request and you serve a response. But maybe I'm missing something.
Email stuff of course still interests me because it's my day job. What's fascinating about my day job is that it's entirely built around people breaking the system and doing "weird" things, and me having to fix stuff. The most recent example was spammers sending QP encoded emails with high bit characters. That broke my QP decoding routines, but it also is a 100% spam indicator.
So is what is actually new and interesting that I should be looking into right now to keep my skills honed? When the web was dying (i.e. around 2000) it was XML, and learning and working with that served me well. What is interesting now?