Twitter earned a far bit of notoriety when the service was first becoming popular for the Fail Whale display. Which basically meant the service was down (normally due to bandwidth restrictions). The whale was cute and gained acceptance, perhaps even a fan base. This let the Twitter engineers focus on fixing things rather than fire-fight complaints. I haven’t seen the fail whale in a long time.
Flickr has been running into a few problems lately, superficially since February and often just regionally and are displaying this photo with the title Bad, Bad Panda. Flickr is apparently undergoing some pretty heavy updates, many are scheduled, which I assume are related to the new user display formats. Really it means the site is down and they know about, so be patient. Once upon a time you would get a boring 404 message when a web site doesn’t respond, the Bad Panda screen is a much nicer let down but I don’t think it will be legend like the fail whale.
For those interested here is the story behind the Bad Panda Picture.
If you want to check an on-line service you use often and doesn’t seem to be responding. Fist of all check some other site (like the google query page) to make sure your access to the net is working. If the site is still not responding you can use a net called Is It Down Right Now?