Any interactive website you visit on the Internet these days has web applications running behind it. The applications do all the work and most content is generated on the fly - as opposed to the old model where static pages were served from a web server somewhere. Gone are the days when plain HTML was sufficient to give you a web presence - users demand (and deserve) a highly dynamic web experience now, complete with multimedia and personalized browsing.
There's also an increased shift to developing web applications using regular software development cycles and models. Websites are now versioned in content management and versioning systems just like your typical enterprise product. Build cycles exist and well as integration cycles and such.
Web development tools also continue to take prominence. No one writes code from scratch these days - that's under-productive, like reinventing the wheel. Instead, serious developers maintain templates or use rules-based code generation engines. I particularly like tools that can take all my UML junk and produce code from it - all the classes and stubs I will need. So much time savings there.
In mentioning tools, you've got to consider IDEs and plugins. It is no longer sufficient to know how to use only one IDE because projects come in all shapes and sizes. I routinely use NetBeans and Eclipse on the same project, for example, because of the various benefits each offers (especially in the area of add-ons). Mind you, each skill you will need to use may have its own IDE, so you've got to stay on top of it all.
Finally, it's a can of worms when you consider personalized browsing. Everything from targeted ads, to personalized look & feel, to presentation of related content and session management fall under this umbrella. It's a sort of social engineering done in software, once again eased by rules-based computing. Beyond that, reporting strategies, tracking, data warehousing, and all that crap I don't do well - the web application isn't complete until most of this stuff is in place. Web development is no longer a piece of cake.
So those are just a few observations from my latest project. I'm actually relieved it's over - it was beginning to drain the life out of me.