"We're Upgrading" "Under construction" "Under maintenance"

I'm also amazed by all these messages that you can find on some websites such as "We're Upgrading" "Under construction" "Under maintenance". You'll have the impression that these guys are really working hard on improving and sustaining the site. Well, I'll tell my opinion. I think that Webmasters leave these messages when they screw up some codes. Some of you may have also encounter websites where they stay for months, even years "under construction". I really wonder what type of raw materials and what procedures are they using because they take time enough to build the whole planet Mars.