The Tipping point?

I've just seen something which represents a tipping point, the point at which something just starts to grow for no apparent reason.

I placed some guroo learning resources on TES Connect a while ago. For months, they were ignored until August, since then 27 requests for the resource, more than 1000 downloads and a 5 star rating.

And every week, we get more - another 5 genuine enquiries this week from potential customers.

I'd like to say I could work out why something like this happens, but I can't!