Tom from MySociety sums it up:-
I'm sceptical about his last line there, for me it was only about receipts, nothing more. It reminds me of the way Socialists try to hijack any demonstration or anti-war march, most people are only signing up for the thing they're signing up for, nothing more.
This is a huge victory not just for transparency, it’s a bellweather for a change in the way politics works. There’s no such thing as a good day to bury bad news any more, the Internet has seen to that.
Over 7000 people joined a Facebook group, they sent thousands of emails to over 90% of all MPs. Hundreds of thousands of people found out about the story by visiting TheyWorkForYou to find something they wanted to know, reading an email alert, or simply discovered what was going on whilst checking their Facebook or Twitter pages. Almost all of this happened, from nowhere, within 48 hours, putting enough pressure on Parliament to force change.
Make no mistake. This is new, and it reflects the fact that the Internet generation expects information to be made available, and they expect to be able to make up their own minds, not be spoon fed the views of others. This campaign was always about more than receipts, it was about changing the direction of travel, away from secrecy and towards openness.
Anyhoo, this is the most up to date graph of membership accumulation for the Facebook group that's getting credit for it all.
When you're speculating on this sort of thing in future, its not going to be about breaching the 10,000 member barrier to get media coverage, its going to be about getting members and getting them motivated quickly. Its the gradient of the graph thats important, not the height.