I just got a pop-up on a Web site, inviting me to buy a "Fish aquarium screen saver".
It reminded me of the early 1990s, when "After Dark" was the cool screensaver to be seen using. Instead of some boring bit of text, you got these neat fish swimming across your screen, with a really cool sea-bed at the bottom.
Then a colleague pointed out to me: unless you select the option that removes the seabed, it's not really a screensaver - all you'd end up with is an image of a seabed burned into your CRT in place of the Mac desktop you'd have had otherwise.
15 years later, of course, we've learned our lessons. Or have we? There was a quick demo on the aforementioned pop-up, showing what the screensaver looked like. And guess what ... loads of nice static seabed and rocks and stuff.
So all you utility software writers out there: when adding on the bells and whistles, don't forget what you started writing it for in the first place.