The unprecedented gap in Methods of Rationality updates prompts musing about whether readership is increasing enough & what statistics one would use; I write code to download FF.net reviews, clean it, parse it, load into R, summarize the data & depict it graphically, run linear regression on a subset & all reviews, note the poor fit, develop a quadratic fit instead, and use it to predict future review quantities.
Then, I run a similar analysis on a competing fanfiction to find out when they will have equal total review-counts. A try at logarithmic fits fails; fitting a linear model to the previous 100 days of _MoR_ and the competitor works much better, and they predict a convergence in <5 years.
Master version: http://www.gwern.net/hpmor#analysis
Some alleged chapter reviews may be for the work as a whole rather than the particular chapter. Such reviews are likely to accumulate on a particular chapter when that chapter is the last one and there hasn't been an update for a while. That could explain why the faster pace in the 40-70 region lead to less reviews per chapter. Even for chapter-specific reviews I'd guess people are more likely to write a review when they haven't got a new chapter to immediately go on to.
There's clearly a 'dead-end' effect, yes - you can see it clearly in the first graph, with the thick black bar each chapter receives, proportional to its time as the 'latest' chapter. EDIT: you can also see this effect vividly in the Unexpected Circumstances per-chapter graphs.
But I don't see why this would distort an entire region compared to another region: every reader in the 40-70 region is going to dead-end in the 40-70 region, almost by definition, unless they start reading at the very tail end such that an update happens before they finish that region (and would leave a dead-end review, one chapter before).