[andosteinmetz]

I think the reason is that many of the problems JQuery was designed to solve (DOM manipulation, cross-browser compatibility issues, AJAX, cool effects) have now been implemented as standards, either in Javascript or CSS and many developers consider the 55k minified download not worth it.

http://vanilla-js.com/

[bengotow]

That reference is good but this is a better side-by-side I think: http://youmightnotneedjquery.com/