Wow, cool, I've been looking for this for a while:

<p>"Sketches" are a type of algorithm that summarizes stream data.

<P>Count-Min is one of the most important algorithms:

<ul>
<a href="http://www.reddit.com/r/programming/comments/q6mht/heavy_hitter_detection_using_sketches/c3v5w2t">[1]</a>
<a href="http://amatsukawa.posterous.com/heavy-hitter-detection">[2]</a> 
<a href="https://sites.google.com/site/countminsketch/">[3]</a>
<a href="http://blog.aggregateknowledge.com/tag/count-min-sketch/">[4]</a>
<a href="http://www.stanford.edu/~ashishg/amdm/handouts/scribed-lec5.pdf">[5]</a>