Overstock, the secondary market retail website, has been blocked by Wikipedia.
Due to the spammy nature of Overstock on the user-generated encyclopedia, the company's IP range has been blocked, meaning edits and entries can no longer be made to Wikipedia from this range of IP addresses. Also noted as undesirable behavior from the folks at Overstock are attempts to intimidate administrators that have tried to curb their spam. A Wikipedia individual initiated the block, and has left a message for all other users encouraging them to keep the block against Overstock.
With Wikipedia's revised edit-management system still being tested and tweaked, more sites such as Wikiscanner and Wikirage will come in handy for the self-regulation of Wikipedia.