I would not be surprised whatsoever to hear that a site gets nailed by Panda after adding 1 million pages of less than ideal content
.... almost a certainty. Where do you get so many pages of unique and compelling content from?
Managing large organic sites is likely impossible for sustainability , unless you scale them from solid foundations with good techniques and solid content differentiators. Same subject , different words is not good enough. Google wants a different and compelling user experience to compete around what it can do itself or has plenty of.
So if you're investing heavily in rebuilding content with different words, think again. There's much more to the strategic direction of Google than shifting the " deckchairs on the Titanic".
The mentality for copying or building similar sites to compete with what the next guy/gal/business is doing needs to be radically adjusted to embrace these changes.
Support your niche with things that Google and competitors cannot do as well as you. Combine information, usability and relationships in a captive combination.
Again, more talk around this type of thing and sharing will help elevate folks to new levels of creativity and solutions.
Lurkers ... come in from the cold and be bold :)
[edited by: Whitey at 11:30 pm (utc) on Oct 5, 2011]