It's a mark of how reliable some websites are that the first thing you do when you can't access it you assume it's something up at your end. As it turns out the BBC has suffered a major DNS outage knocking all four of their DNS servers off the 'net. At a stroke anything with a bbc.co.uk domain name became inaccessible. It seems this was due to routes to the DNS disappearing (similar to how Egypt disconnected itself last month).
When major sites like the BBC go down it's real time services like Twitter that come to the fore. We spent a good half an hour chortling at a number of humorous tweets that exploded a minute or so after the outage. You can see the peak of activity on Google's real-time search. Of course the value of this real-time information quickly falls off as spammers and conspiracy theorists jump on the meta-tags to promote their own products and theories. This included rumours that Anonymous was responsible for bringing down the BBC.
It's a salient reminder for all the "invulnerability" of the Internet high availability is a hard problem to solve.
UPDATE: It's ironic that my post hasn't made it's way to my LiveJournal mirror yet due a separate outage that seems to have lasted most of the day.