pageoneresults - 4:46 pm on Mar 16, 2011 (gmt 0)
I hate using these tags, just as I hated using nofollow way back when. But sometimes, it seems necessary. Is their any downside to what I've done with the noindex, follow? Is Google likely to give a crap that I've just told it, that it's not to index half a million pages?
I strongly advocate the use of noindex or, nofollow or, noindex, nofollow. The follow directive is the default behavior and is not part of the protocol. You use the metadata to prevent something from happening, not allowing it to happen.
In the case of aakk9999, I would think you'd want to 301 the majority of this back to an upper level where it belongs? Like to the point where the bot SHOULD have stopped? This way you are able to maintain some of the equity but I wouldn't think there is much there if the indexing was brief. My educated guess would be that you'll just go through another recalculation process after a new indexing reveals the updated directives.
There also might be further delays in the short term while whatever trickle down effects are worked out. Technical glitches can wreak pure havoc on indexing and crawling. In fact, I've seen Googlebot do its best to warn site owners that there is a problem (via GWT) and then boom, their pages start to disappear. In the mean time, GWT shows the bot activity and the early warning signs but no one knew what they were seeing. You have to pay close attention to all this stuff. ;)
301 for content that has an equivalent replacement.
410 for content that is Gone.
Those are really your only two options. Google will treat that 410 like a URI Removal Request and it will be Gone shortly after the bot receives instructions. It is rather quick. In your case, you really need to instruct that bot to forget about the previous indexing directives and to permanently change those instructions. That means a 301 for most of what you have going on.