Start.io is an engine for creating customized start pages, with the added bonus of letting you know when your favorite sites have updated. It comes equipped with a drag-and-droppable interface for adjusting and grouping your links, and several nice-looking preloaded layouts to choose from. On top of that, the CSS is entirely customizable, so you can modify existing layouts, or build your own from scratch.
The first thing I wondered about Start.io was why it just lets you know that one of your links has updated, instead of using RSS to show you exactly what the updates were. The answer (explained on the about page) makes a lot of sense: you don't come to your start page when you want to read a bunch of RSS feeds. You go there when you want to click through to the sites themselves, not Google Reader or your standalone RSS app. If you want an RSS reader as your start page, there are other services you can check out, but I haven't see a complete start page engine like Start.io anywhere else.
What's your start page? Do you like Start.io, or do you have a better alternative? Let us know in the comments.