I'm going to be honest and admit that I'm still not entirely comfortable with calculating this metric. I've just been going into Google Analytics and dividing our weekly "Users" graph by the previous week, and then averaging all those percentages together. Same for monthly growth. I'm assuming, from people pointing out errors, that this is not the correct way of calculating growth?

Regardless, we've seen significant and consistent increases in traffic, but I'd definitely like to not sound like an idiot (or worse, have my errors be decried as misrepresentation), in the future.

This was actually the thing that leapt out at me - I don't really have experience of investors except watching Dragon's Den(!) but they've always been super-harsh on those that misrepresent their figures [or at least are caught doing it].

1.4^5 ~= 5.4

Make sure you're being truthful about your figures with yourself - like don't assume you're making a profit just because you're taking revenue, especially not if you're not paying wages yet.

I assumed that the latest w/w is 1.4, whereas the m/m includes earlier weeks that aren't as good, eg. 1.1 x 1.1 x 1.2 x 1.4 ~= 2.03