I used to work in a Company where Easter Eggs used to be considered a feature and there used to be a official maintainer for it (I used to maintain both the Easters listed here and more). I used to feel that Microsoft shouldn't have moved away from inserting Easter eggs and should've stuck with funny messages in its Software. Microsoft Max (now canned) use to give really funny messages like suggesting that I get coffee as the installation may take some time.
However, with time I have realized that funny messages are not always funny (even though I still believe Easter eggs are). If you look up the demographic usage data of Orkut it is mostly used in Brazil (60%) and the 3rd highest usage is in India (12%) and growing astronomically. Server failures in Orkut is given out as a "Bad, Bad Server. No donut for you" message. Now the problem is in India we do not eat Donut and I have a ton of non-geek friends who've never been to the US and have no idea what a donut is. One of them got majorly irritated with the message.
I guess for free services where there is no paying customers it's OK to have these kind of funny light-hearted messages, but still you need to target your jokes well. Lets hope in the Future we have India servers throwing up "Bad Bad server, no Vada for you" messages :)