Have we had a thread on this yet? Lots and lots of people I know have joined in the last 48 hours, and yesterday they overtook UKIP's membership total. Facebook is pretty much a Green Party feed for me at the moment. Would be really interesting if this turned into a big media story and led to a corresponding surge in their opinion poll ratings.

But what does it actually mean? Do all these people actually want to go to local meetings, get involved in policy discussions and get out on the doorstep? If they just want to pay their £2 a month to show support and talk about them on social media, is that really like being a member?

But then again. what is party membership these days anyway? We know that the model of mass membership parties is dying and threatening the existence of the big parties, so maybe my expectations of what people are signing up to is just out of date. People don't think of it that way any more.

But one person I know joined yesterday, but isn't even planning to vote Green in May. They don't want to give the Tory candidate a chance of unseating their local Labour MP. I was stunned that you could want to be a member of a party you don't intend to vote for, but she said she wanted to send a message to OfCOM and the BBC that the Greens should be included in the TV debates. So a tactical membership, rather than a tactical vote, I asked? Yes she, said, exactly.

All really fascinating stuff, and it feeds into the story of traditional politics - not just parties but they way we vote for and interact with them - is disappearing fast.