For the last week or so, I have seen different Googlebot behavior compared to the last three months. It used to be that my site would be visited once a day, every day, and that new pages would be picked up and indexed a few hours after Googlebot's reading of the page that links to them. However, this is not the case anymore. Googlebot still visits every day, but new pages are not being picked up. This has been going on for almost a week now; I have seen the odd hit on a new page (all html, btw), but none of them show in the Google cache. The daily visit just cyles through the old pages Google already new. Also, 404s are not being processed properly, in that the page that disappeared is not removed from the SERPs, also for about a week now. Has anyone observed similar change in behavior, or is it just my site? I'm a bit worried that my new pages create some kind of problem for Googlebot, although I haven't been able to find anything obviously wrong with them.
Duh, can't you read? The OP said that this started happening ONE WEEK ago, NOT months ago, so your reply is NOT the answer to HIS problem.
In his case it was a week with his site, i am talking in general because i am running 20+ site under me right now, i am saying on my experience.
As long as you didn't add in "nofollow" for the pages it seems normal. Make sure those new pages are built within the index page of your website. It also helps Google a lot when you build links to those new pages. Give it some time as it seems normal to me.
Google is always updating its algorithm. Some sites will be affected and some won't, it all depends on how you have your site setup and your linking profile. As long as you haven't done anything gray or black hat it will be fine. Just keep creating new, original and relevant content and building natural links and you will continue to rank. My sites are always fluctuating, could be Google, could be what I am doing or it could be what my competition is doing.