I guess about 2 years ago many referred to the Bloglines Plumber as a new way to deal with error and maintenance messages, and users loved it. It was definitely something else than the regular 404 or maintenance pages we were used to seeing so this was refreshing.
But it wasn’t (or isn’t) only the funny Bloglines Plumber that built this image. First of all you wouldn’t see it that much (at least I didn’t) and if you would, most of the times it were for an update to the service. And we all like new stuff to be added to the services we like. Second, the support of Bloglines is very good. Whenever I mailed them with questions/requests they always came back to me.
Bloglines wasn’t the only one to communicate maintenance and errors in a funnier way. Technorati has their monster …
… and Twitter their catz.
The problem with the last 2 is that you get to see these messages all the time (why don’t they just work?) and their support is not what it should be (ever sent email to Technorati with a request?). It has always amazed me how a company like Technorati – which helps you listen to the conversation – actually doesn’t listen that well themselves.
Whatever the error messages look like, in the end we prefer just not to see them at all. And I think that in the conversation age it would be far more usefull that you tell us what the problem really is, especially when you’re clearly struggling with something over a longer period of time like Twitter has the last few days.
'Cross The Breeze 
You forgot Flickr with ‘Flickr is having a massage’:
And iStock with this cute error critter:
Thanks Bart – I hadn’t seen those yet, they fit in pretty well indeed :)