However, I overlooked one possible cause. As you may know, Alexa has historically gathered its analytic data via a toolbar, voluntarily installed on a browser, that reports the web site visits of each user. There has long been criticism that the toolbar, which is not compatible with all browsers, causes bias in the data, particularly since it may be more likely to be installed by some types of web users.
This spring, Alexa expanded its data sources and made changes to its algorithm. This caused many users to see shifts in their Alexa rank.
When the formula for calculating traffic is changed and we don't know how, it calls into question all before and after data comparisons. We'll have to wait awhile and take a look at six month data.
One thing has me scratching my head. Was the Alexa toolbar over-reporting webcomic visits, or under-reporting visits elsewhere? If the original toolbar demographics are ever released, it might tell us more about our own demographics.