Over the past 3 weeks I can compare any given day this past week with the same day in the previous two weeks and see that my site received nearly the exact same number of visitors regardless of which day I picked. I first started checking when I noticed a pattern of three days in a row ending up with the exact same number as two weeks earlier.
So why is that odd? Because over the past four weeks I have been writing new content and promoting the site a great deal to make up for a minor loss in traffic some six week earlier. The site received a minimum of nine new pages and up to 14 new pages per day during those four weeks.
All new content is indexed but none ranked well, until tonight. Tonight the articles I wrote three weeks ago seem to have been 'unlocked' in search and are on page one for various semi-busy keywords and they have begun receiving traffic. All articles 17 days or older were unlocked, all articles 16 days or newer are not.
To me this strongly suggests that indexing and and ranking are on two very different schedules, the later being much slower. I have previously written articles that ranked fairly quickly, almost as soon as they were indexed, but that seems to be an exception recently.
Are you seeing the same thing with your new content and traffic levels from Google? With all the talk about Caffeine it seems a little odd to be gaining traffic in spurts despite regular content additions.
I suspect that Google's computing resources are being allocated to fixing their existing SERPS at the moment. Even some well established websites are bouncing around the SERPS like ping pong balls.
Your timeline correlates with many complaints that started rolling into Google. Supposedly an issue with missing parked domain data, Matt Cutts said it was fixed. It does not look "fixed" IMO and newly created pages are indeed seeing a significant delay in ranking.