Search: Google Cache oddity

I’ve just noticed a slight “oddity” with my favourite search engine Google. Basically, Google has a cache facility which enables your to see what the page was like when Google indexed it using their Googlebot spider. Extremely handy if the site you are trying to access is unavailable for some reason.

Google also offer the Google Toolbar for Internet Explorer users (a Mozilla version is also available) which makes available certain items such as “Search From Toolbar” (saving you going to the Google homepage) and direct access to the cache.

Now, here’s the oddity: Accessing the cache of my blog via the Google Toolbar gives me a URL in the format of http://216.239.39.100/search?q=cache:http%3A%2F%2Fblog.rac.me.uk (ok, there are a few more parameters, but I’ve reduced them to “bare minimum”). That link currently shows my blog with the latest entry dated November 13 2002 at 12:31am (entry “Game: Fling That Cow!“) – however, performing a search and then clicking on the ‘Cached’ link produces a URL in the format of http://216.239.39.100/search?q=cache:QGa9rQIfcj0C:http%3A%2F%2Fblog.rac.me.uk – with a “last entry” date of December 15 2002 08:11pm (entry Movies: Films I’d like to see again) – just 2 days ago.

So: why has Google got two cached copies of the same page? Obviously the search system is using the “fresher” copy, but it’s still given me a reason to stop and think. And what does the QGa9rQIfcj0C bit mean? A bit of playing has shown to me, so far, that it’s a unique identifier for the page in Google’s cache: searching for other pages from my blog resulted in the code “OdxOQ8hwqvMC” (November 12th: Pick On George Bush). “Adjusting” the cache URL to read http://216.239.39.100/search?q=cache:OdxOQ8hwqvMC:blog.rac.me.uk still shows up the individual entry page instead of the front page (which you would have thought by the format of the URL). fEJraafpn4cC is the code to my Games and Fun category page

Someone else has noticed this at Webmaster World, but no useful information came from that discussion.

Oh well – if I find out anything more (it’ll be interesting to find out if the “cache IDs” remain static over time), I’ll let you all know 🙂