There was a live audience of 300+ people, most of whom weren't (to my knowledge) librarians, and plenty of whom seemed to enjoy and understand what I was saying:
Since I uploaded my slides yesterday lunchtime they've been viewed 700+ times, and are currently featured on Slideshare's Education page. Video of the speakers will be added to the Ignite website soon, and should reach a few more people. So all in all, I think this counts as an echo chamber escape!
Ignite was a real blast. A big thank you to the organisers for choosing me as one of the speakers, and for their hard work in making it run so smoothly. Probably my two favourite presentations were Andrew Betts' 'How standards changed the world' (from Roman swords to time zones to aircraft to the magic of A4 paper) and Paul Clarke's 'Music is mostly about cheating' (the Pythagorean Comma lucidly explained in 5 minutes - magic!). A special mention also to Maxwell Roberts' beautiful tube and metro maps.