I have heard many people saying that while Google Dance you cannot be sure of your PR. What is Google Dance and why does it is called so?
There are many Google servers and your site ranking can be slightly different on these different servers. This is called as Google dance..
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Yes, I have noticed this with some my websites! They have different Google search engine ranking positions!
Or you are using different tools for checking your PR. Anyway, the PR you can see is only the one Google wants to show. It is not necessaryly your actual PR.
There's not really such a thing as the Google dance anymore. It used to be the case that Google would update their indices on a regular basis. The web community even gave them names. See below: http://www.webmasterworld.com/forum3/2657.htm Google tweaks their secret formula a number of times every week now so its not as noticeable as it used to be.
If your tool to check PR is Search Status, don't so trust on it. Use google toolbar for the correct one. I have same experience like that also.
Once in a month Google updates its entire database of websites and during that period rankings might fluctuate. After the Google dance completes you can see a stablized ranking.