My Society http://mysociety.org is a wonderful force for web-based democracy (a project of UK Citizens Online Democracy (UKCOD)).They change the world by building software for democracy. They've now released a version of their Mapumental software that covers the whole of the UK! Property (http://mapumental.com/ ). You simply type in your postcode and slide the time that you are prepared to travel by public transport. Here's chemistry in Cambridge (CB2 1EW) for 25 minutes to arrive by 0900. Stunning. And of course it all relies on Open Data (imagine if you had to ask the bus company for permissions).
And here's another of their great projects. FixMyStreet works for the UK but the software can be used anywere.
FixMyStreet - anywhere in the world
FixMyStreet covers all of the UK. But we can't build street-reporting sites for the whole world, so friends abroad may like to know that we've made it easier than ever before to set up your own version.
If you've ever thought about building a site like FixMyStreet outside the UK, now is a great time. DIY mySociety is our ongoing project to make it easier for other people to build websites using our code - that's the first place to check in for help and support.