Why is the measurement on questions asked for the first couple of graphs and then user traffic for the latter set? I wonder if traffic is the better measurement for the first two as well but I bet the graphs won't look quite as doom and gloom.
The later graphs use data that's already not public (what tags users visit together, and what countries tags are visited from), so there's no reason not to use visits instead.
The graphs for visits over time do look very similar (in general question traffic by tag roughly matches questions asked, but as a slightly lagging indicator)