Even with the EE 2.0 release in December, I think the best ExpressionEngine event in 2009 was the rise of Travis Schmeisser’s Structure. While 2.0 lays the groundwork for a bright future, in the short run it’s more of a step backwards because so few of EE’s amazing community-built addons have been ported so far - even with new functionality, a 2.0 upgrade takes away far more than it gives at the moment.
In contrast, the Structure module immediately makes major improvements to your site’s UI, construction, and template codebase, and it also plays nice with other addons, creating a faster, smarter EE experience. No software I installed last year saved me as much time and effort as Structure did, and Travis deserves all the credit for that (and he got quite a bit, including Devot:ee’s Module Of The Year award).
I couldn’t agree more with that last sentence: Structure has quickly become an indispensable EE add-on, one that I use on almost every one of my EE sites.