I gave this presentation [PDF] at the Vancouver PHP Users Group this evening. I actually really wasn't happy with the first part of the presentation...I genericized large chunks of it, shying away from naming specific web technologies. But, this past weekend I dove into the world of Greasemonkey, and I really felt it had a place in any presentation on Web 2.0, so I had a whole section at the end devoted to it.

The reference to a "layer cake" is really talking about the different components that work together in web applications. This might be in a single application -- the Apache-MySQL-PHP (or AMP) that is quite common -- or it might be different services and content all mixed together. Greasemonkey provides another, richer layer.

The big thing for Greasemonkey was the actually demonstration. Conveniently, I had Safari to show the non-monkey-version, and then switched to Firefox to show the other version. Follow the links below for the user scripts:

• Adaptive Path essay on Ajax
• Wiki of all Greasemonkey User Scripts
• Lickr: replaces all Flash in Flickr with a DHTML/JS equivalent
• Gmail Persistent Search: works like smart folders for your Gmail account, letting you save and repeat searches
• Google Search Keys: add numbers next to your Google search results, press the number to go directly to the page

I also had FlickRate installed but hadn't enabled my account yet. It allows you to rate Flickr photos. I don't like the fact that you have to fill out all three options -- some pictures I just want to vote on as fun, for instance -- but it's still an interesting application.

One idea that was mentioned in the audience as we were discussing was the concept of building a site that is broadly accessible and functional, and then building your own Greasemonkey script to distribute to power users and influencers.

We also talked a fair bit about security. I'm no more or less worried than any other user installable programs, but there were a couple of head shakes in the audience about the potential havoc that this could cause.

If you want to keep up with Greasemonkey developments (and other Web 2.0 stuff), check out Simon Willison's blog. He's been my guide over the years, starting over at Evolt.org, to cutting edge web technologies.

Thanks to the Vancouver PHP Users Group for having me. Upcoming presentations include one on Moodle and another on remote XUL applications with a PHP backend, both of which I'll likely attend.