== LinkSpam == 

 I noticed on 8/23 that you removed an external link (to http://image-processing-is-fun.blogspot.ca/2011/11/one-of-first-edge-detection-filters-one.html) on the Sobel Filter page as linkspam (see http://en.wikipedia.org/w/index.php?title=Sobel_operator&action;=history).  I'm guessing this is because the linked site is not from a "notable" source?  However, in many other articles like this one, that describe a computational algorithm, external links to code implementations of the algorithm (which this is) have remained for quite a while.  This was actually a pretty useful link for anybody trying to deal with the Sobel filter (I noticed it was gone because I was trying to find my way back to it through Wikipedia!)  How is notability applied when linking to, say, open-source implementations of algorithms on Sourceforge or elsewhere?  Every algorithm I can think of that has a wikipedia page has a (few) external links to implementations from non-notable sources.