Last week Joe and I attended Over The Air - a developer-centric conference focused on mobile phone technology and applications. It had been 18 months since the last conference, and the first thing to strike me was just how much has changed in the mobile landscape. A year and a half ago, the iPhone had only just started to impinge on mass consciousness and the Apple App Store hadn't even opened. Nowadays, every new phone launched vies with the iPhone for features, and there are over 20 different app stores - run by platform owners, mobile carriers and independents. This change becomes even more striking if you consider how little has altered in the world of desktop computing, or even web apps, in the same amount of time. In short, the mobile space feels now very like the start of the dot-com boom in the 90s: expect a lot of innovation, a lot of failed ideas, and a lot of attempted land-grabs by both incumbents and newcomers.

Keynote address in Imperial College's Great Hall

With six separate tracks, and a day-and-a-half's worth of lectures and workshops, it would be hard to list everything that went on, but here are a summary of some of the trends that I identified:

• Things are moving fast (see above)
• The rise of web techniques (Widgets, PhoneGap etc.)
• The rise of Linux (Android, Maemo, LiMo)
• Increased fragmentation (more platforms to support)
• Standardisation efforts (e.g. OMTP and BONDI)
• The rise of the App Store (see Distimo's report)
• Augmented Reality is the buzzword du jour

I enjoyed almost all the sessions I attended, but a couple deserve special mention:

• Many Paths Up the Mobile Mountain A collaborative session run by Tom Hume of local company Future Platforms, in which participants had to paper-prototype a mobile application
• Augmented Reality Development Platforms A session by Mark Kramer of Mobilizy, promoting the open ethos of the Wikitude AR development environment

A wooden phone used for paper-prototyping at the Many Paths Up the Mobile Mountain workshop

As well as the formal sessions, it was great to mingle with other participants, many of whom had traveled from other European countries just to be there. Thanks to Andrew Savory of LiMo for interesting discussions about the use of Linux in handsets, and Simon Johnson of Simon Games for sharing his insights into street games and pervasive gaming in general. As well as the formal sessions, Friday turned in to an all-night hackathon, in which teams worked to create the best mobile app. I paired up with Jez Nicholson to create OpenPlaqueDroid - an Android application to let you see information about blue heritage plaques in your area (with data drawn from the OpenPlaques website). It's a very early prototype at the moment, but we have grand plans, not least of which is to add an augmented reality interface using the Wikitude SDK.

Screenshot of OpenPlaqueDroid version 0.0002alpha

Coding in the dark: all night hackathon

The judging session on Saturday showcased some interesting and innovative ideas. You can see the full list of winners here, but I particularly liked:

• Project Bluebell by Future Platforms: an application to generate a soundscape from all the bluetooth signals in the area
• Friend Hangman by Makoto Inoue: a widget (and website) to guess Twitter usernames for people that post with a given hashtag
• Bottle Rock It by Lastminute.com Labs: A networked kazoo orchestra created by blowing on iPhones

All in all, this year's event was hugely enjoyable. A big thank you to all the organisers and sponsors. More info:

• Over the Air site
• Flickr Pool
• Twitter feed
• Radio 4 feature (starts at 25 minutes)

Thom Hopper holding his hand-drawn yet fully-functioning QR code

A dalek guards the main hall