Yesterday's summit on "The Future Of Web Apps" was a thoroughly thought-provoking day, with some great presentations that changed my mind about one or two things, reassured me about others, and set me thinking in new ways about others.

Highlights of the day for me were the opening presentation from Josh Schachter of del.icio.us, who captured just the right tone for the mostly-techie audience without getting bogged down in detail, and Tom Coates of Yahoo!, who took a step back from the coalface and gave some very insightful takes on Web 2.0 in general, and URL schemas in particular.

Tom's presentation, in conjunction with those from Josh Schachter and Cal Henderson - the coder & architect behind everyone's favourite photo-sharing community Flickr, as well as everyone's favourite shrine to juvenilia b3ta - was what changed my mind about URLs. The key point that stuck in my mind was this - everyone would agree that if you expose an API to your application, it should be coherent, be consistent, and "make sense". If your API doesn't "make sense", it won't get used.

But the URLs that people/machines use to interact with your application are actually your primary interface - your primary API - and should be planned out just like any other. If your URL schema is consistent and easy to guess, people are more likely to use your site. If not, it's going to put people off.

The reassuring aspects were related to scalability and re-engineering - the unanimous message from the collected Web2.0 poster boys was that you can't possibly guess what's going to happen and where your app will feel the strain, until it happens. You can design your system so that configuration changes are easy to make, and prepare for the unexpected, but refactoring and re-engineering is an inevitable part of a system "growing up".

The award for Silly Mashup Of The Day will definitely be going to Tom Coates' prototype Astronewsology (don't look for it, it's not live yet...), where you can navigate Yahoo! news by star sign - What happened to famous Capricorns today? - and cross-reference what should have happened to someone with what actually did happen. It was a great example of the kind of horizontal cross-cutting of data that is at the core of Web 2.0 - navigating one datasource by means of another.

There were lots of other points to note in the day, and plenty of food for thought, but if I listed them all, this post would be the length of War And Peace - Carson Workshops were recording the whole thing, and will be making materials available soon.

All in all, a thoroughly worthwhile day, with lots to think about moving forward. When's the next one, Ryan...?