Gwern Branwen wrote:
"User:MBisanz has charted the number of new accounts registered per month, which tells a very similar story: March 2007 recorded the largest number of new accounts, and the rate of new account creation has fallen significantly since then. Declines in activity have also been noted, and fretted about, at Wikipedia:Requests for adminship."
My take on this is that all this tells a story of ever fewer people joining, and casual editors continuously winding down & leaving. This means that the small group of dead-ender hardcore editors will grow as a percentage, which may seem like a good thing ('yay, more editors are becoming obssessed!') until you consider the larger picture.
(My cynical sarcastic take on this is to thank all the reference nazis & deletionists & vandal-fighters; we couldn't've done't without ye!)
But note that most accounts don't edit _at all, ever_. Account creation may be the simplest statistic to get, but it is also the most simplistic.
The English Wikipedia is around 10,000 editors, basically.
Charles