Sites dropping in Google SEPRS

I have been creating a decent amount of Adsense sites with keyword domains. Each site has entirely unique information and 3-5 pages. All of the designs are unique, from different free CSS templates.

These sites do very well for the first month on Adsense, maybe 6 weeks and then immediately drop off Google rankings. I've spread them around on 6 separate ips/class c's. The sites remain in Google and offering Adsense, just the organic Google SERPS drops off a cliff. Adsense still pays the same eCPM.

Anyone have a similar experience that made some tweaks?

I did have moderate success with placing the exact same content on a different template, but not really anything significant.

Are you updating these sites regularly? Most of the time you can't just "sit and leave" your sites after they have a good SERP. Not saying that's what you're doing but I had a very similar situation with a few of my blogs, which I hadn't updated in a few weeks.

So I started writing at least 1 post per day, even if it was just 50-100 words. I quickly noticed that the more frequently I added new content, the further back up the rankings they went. Just a thought..

interesting thought. most of these are static sites and haven't been changed all that much. I have tried adding paragraphs here and there, but haven't really made wholesale changes to the homepage. Perhaps that is in order.

New sites get a "New-Bonus" in Google..maybe the Bonus from your sites is over.

I have seen signs of stale sites moving down in SERPs.

By stale i mean not adding new pages. adding and deleting content is a different part of it.

im not sure it is a new bonus issue because the sites aren't dropping by like 50% or even 75% in traffic, but more like 95%

@joyjoy - good point, I may try adding some new pages as opposed to the same old structure and adding/moving/deleting content

Autoblogs might be a good idea as they would be auto updated.