After a lot of speculation Google has finally changed its Cache urls from ip to sub domain. Our blog cache is now showing at webcache.googleusercontent instead of the normal ip as before.
As initially reported at Webmasterworld, now it can be seen across majority of Google Datacenters.
It seems to be a move to decrease the load on the ips and make it easier for users to relate the cache information to.
To quote what are Cached Links from Google:
Google takes a snapshot of each page examined as it crawls the web and caches these as a back-up in case the original page is unavailable. If you click on the "Cached" link, you will see
the web page as it looked when we indexed it. The cached content is the content Google uses to judge whether this page is a relevant match for your query.
When the cached page is displayed, it will have a header at the top which serves as a reminder that this is not necessarily the most recent version of the page. Terms that match your query are highlighted on the cached version to make it easier for you to see why your page is relevant.
The "Cached" link will be missing for sites that have not been indexed, as well as for sites whose owners have requested we not cache their content.