Your graph seems to show that the traffic started to spike on the 3rd of July last year, going completely parabolic within a few days. The price didn't begin to spike until the 9th or 10th of July. That seems to indicate that in the first bubble, traffic preceded price rather than the other way around (of course there is a feedback loop there as well).
In my view, as long as there are rewards and influence available for newcomers (not just the old guard), there will be some growth or at least stability, regardless of price. I think that's where we went wrong before, with influence in the hands of very few and almost no rewards for newcomers. This is borne out in the reward distribution graphs posted by @eroche.
That's not how I remember it, I will have to revisit that
There was a rally to 34c on the 3rd (same day as spike in traffic), but given the volatility of Steem and the fact that it was 44c only a couple of weeks before, that doesn't seem like a major factor. Traffic was definitely beginning to be parabolic even as the price declined from that rally.
First payout was the 4th, so that would have been a little insider buying just before skeptics and the world saw actual coin being paid out, not just promissory figures. Many existing people popped back in to see what was about to happen
There was a good amount of external coverage surrounding the megapayout, starting a few days before, and certainly a lot of excitement among Steemians which may have driven word-of-mouth. The big price rise came well after the megapayout, culminating with the Poloniex listing in later July.
I stand corrected then