I am, but I joined several months ago earlier this year. This is of course a kneejerk reaction to the referendum turning out as it did but that's not necessarily a bad thing. People were joining other parties like the SSP and the Greens - the Greens are nearly as big as Scottish Labour about now, coming up for the 14,000 member mark at least.
For one thing all of the new members are paying monthly subscriptions of a minimum of £1, though many will pay £5 and more. I think I heard that at the lowest the SNP is going to get an extra £840,000 a year if every one of the new members only pays £1 a month; if every new member pays £5 a month it would be an additional £4,200,000 every year. So it's going to be at least around the million/two million pounds figure in addition to their previous revenue figures - I don't know what those are, but they only had 25,000 members last Thursday, so you get the picture.
EDIT: I've just realised I messed up the figures by including the original 25,000. The point is that regardless of how many new SNP members there are exactly; there's about enough to say the SNP are going to get another million pounds or so every year as a result of the membership surge of the last ten days.
The new members are also, I believe, from the central belt of Scotland mostly, so around the Glasgow/Edinburgh area. That's an area where we can make big gains over the next year or so, so it's very handy we've got them on board.