Name: Virusicus Linkilikus, AKA "The Link Leak Virus" (or LLV for the acronym-obsessed).
History: See Martin Neumann's excellent summary.
Symptoms: Healthy pleasure in linking to high-quality resources on a regular basis; lack of selfishness and highmindedness; confidence that blog readers will return if fed good links regularly.
Treatment: There is no reliable way to treat this highly contagious virus. Some have hypothesized that the only way to eradicate the Link Leak Virus is to re-emphasize to bloggers that a blogger's blog is her castle, and that therefore all who enter must be subject to her words and her words only, without any outlinking of any kind.
Disclaimer: The information above is meant with a dash of humor and not to be taken seriously as a notice of any physically harmful virus :). Also, the more a person succumbs to this powerful virus, the more he envisions the Web as a tool to connect people, rather than to disconnect them. Truth be told, I wish all people were infected with LLV. Especially corporate bloggers who think their business blog is the only resource worth linking to.
Now go spread a little link leakin' love while you gear up for Blogtipping Day on June 1st, 2006!