At first glance I thought the title inferred that Tumblr hadn't increased in traffic in two years, which was very confusing. A better title would be something along the lines of "Tumblr now does as much traffic in one day as it used to do in one month."
Really bad title, were you trying to optimize it for twitter?
On the first read it sounded (to me) like nothing had changed, it wasn't until I actually clicked through and read the full headline that it made sense.