This is a really good way to get rid of ads, and it isn't too hard to deploy. AdBlock extensions will also increase your browser's RAM consumption, not only overhead from the extra javascript and layout data, but each iframe can take over 4MB extra overhead, due to how the adblock extension works (injects a large stylesheet into each frame that has filters for every advertisement it knows of).
As a test, load a page with a lot of frames such as this Vim Color test page:
http://vimcolorschemetest.googlecode.com/svn/html/index-c.html and try it with and without adblock, then compare the memory consumption.
For most, this is rarely a problem