Viewing source has gotten pretty rad these days! Looking around the web, a good command + u (yes, I use Firefox/Mac) can provide an afternoon of exciting show and tell. One thing I like to look into is at which DTD table everyone is sitting these days. When the HTML5 doctype was introduced, some folks grabbed it and never looked back to the land of system identifiers again; others were cool with rocking a doctype that has been working for them for the last decade or so. This has caused some separation between those who see the choice as the past versus those who see it as the future. The cool table versus the lame table.