Somehow, browsers or web standards will soon evolve so that a link like this:
example.com/page.html?highlight="the phrase I wanted to call your attention to"
will make the page at the link look like this:
The forum software package vBulletin does this (it changes the text color, not the background, but either works for me). Some websites create a special link if you copy a block of text from one of their pages (it's usually the URL with an appended octothorpe and code number) that does this, as well. It's very handy when referring to long posts, and I think the concept should be generalized. Who's with me?
Also: can I file this post under Web 3.0 Teh Semantic Web!!!1!, just to inflate my Web Evangelist™ cred?