it stands for: a spurious blog

"Splogs" are amateur blogs with mostly stolen content that are published by spurious bloggers -- known as "sploggers"-- for no other purpose than to carry the advertising that Google pays to display on a PPC (pay-per-click) basis.

Here's an example of its usage as seen in the The Guardian (in the U.K.): "If you set up a few thousand splogs, use Google's AdSense ad-serving programme to line the pages of the blog with click-through adverts, the money will roll in while polluting search results for everyone else."

See also : bandwidth hog  crog  
NetLingo Classification: Online Jargon