This post was published a little prematurely. Read the background here: cited.
"Infosuicide" is a term which appears to have been coined recently by Eric Meyer: It's the act of deleting your entire online persona. I prefer "infocide", it's snappier and slightly less distasteful.
The first infocider I stumbled across was photographer, blogger and sometime software author Noah Grey. Noah was the author of the Grey Matter blogging platform and an excellent photographer. In 2007, Noah's partner Barry (whom we learned a little of via Noah's blogging) died, and Noah departed the web as a result.
The second case study is a person who went by the alias "_why", or "_why the lucky stiff". Why was a prominent person within the online Ruby community famously authoring "_why's poignant guide" to ruby, which was amusingly irreverant if not any use as a guide. _why's partitioned identity was clearly important to him, as an attempt to reveal his "real life" given name appears to have prompted his departure. Most, if not all of _why's contributions have been forked and preserved by others in the Ruby community.
The final and most recent case study is that of Mark Pilgrim. Pilgrim is the author of popular tech books including "Dive Into Python" and "Dive into HTML5", all of which were published traditionally but also were provided online in their entirety, for free.
Mark's case is particularly interesting due to his deep involvement in the development of the web. I don't know for sure, but I think Mark was a firm believer in the notion that Cool URI's don't change: certainly his website had semantically-meaningful, permanent-looking links. For someone who in all likelyhood appreciated the value of the permanence of links to so thoroughly remove their material is unusual.
Perhaps the reason behind his disappearance is some grand experiment to see just how reliably valuable information can be preserved on the web, in the face of disappearing hosts and other uncertainty. Or perhaps some "real life" events have triggered it. In recent times, his blogging output had dried up completely. and at the same time his tweets had become increasingly erratic, irreverant and plain weird. The truth may be a mix of both, or neither explanation.
One series of Mark's posts which I found particularly valuable was entitled "A Gentle Introduction to Video Encoding". As far as I know, there hasn't been an explicit effort to preserve Mark's blog writings since his disappearance. However, the Internet Archive has captured these articles, at least. Here's an index:
Whilst writing this article I was pleased to discover that Noah has recently returned to the web (go check out his site!). It's entirely possible that _why is back in the community with an entirely new alias, operating under the radar. That's the flexibility that a distinct online persona gives you. It's less likely Mark Pilgrim is doing the same.