Good to know that I'm not the only one. And not only do I highlight the text, but I just keep clicking, highlighting and un-highlighting. So I'm probably really overloading their servers with the AJAX callbacks.
With respect to NYT, I've found this rule to be quite effective:
|http://graphics8.nytimes.com/js/app/*
Kills that nasty action.
(I do both, and I suspect they tend to go together)
Hmmm, scrolling is not ideal for reading (e.g the Kindle pages, I think). Problem = opportunity, so maybe one solution is a plugin that automatically adds pagination (not actual pages, just mark them with horizontal bars - I think easy enough to do in greasemonkey).