I still say there is no throttling mechanism per se, only the temporary appearance of such. I suspect the new personalization system is still kicking in and digesting a ton of data. The ups & downs are typical of Google every time they fire up a new (major) algo change.
The concept that Google would try to share traffic from bigger sites to lesser sites is hard to accept. Why would they do that? Only wishful thinking here me thinks.
I have noticed that my Wordpress blog is getting more traffic, but that is just supplemental info to my main site. Google seems to like CMS sites because of their clean content / css separation. I figure people will all start using CMS, then Google will decide that using a CMS is black hat...who knows. Any way you cut it (using Occams Razor, lol) the simplest explanation is usually the correct one and the current issue simply seems to be a side effect of the new personalization system, or not.... ;^D
BTW: Traffic and sales are a bit better today.