1. Not updating your copyright. Nothing says “Our website isn’t very important to us” like having © 2007 well into February 2008. Changing it on January 1st says just the opposite. If you want to make life easy, get a script that automatically updates your copyright so you don’t have to.
2. Neglecting to update time-sensitive data, like scheduled holidays if you’re Zions Bank. Argh. They did get the copyright though, got to give them credit for that.
3. Not removing “2007″ as an option on a date picker. Whether it’s a calendar or drop down, if the logic behind your date picker does not allow dates in the past to be chosen, then you better remove the option.
4. Accidentally referencing last year in your content. “I met with Frank on Saturday the 12th, January 2007.” isn’t a good way to start a blog post when you’re really talking about ’08. Be like Michael J. Fox, and remember what year you’re supposed to be in.
Sorry, I could only come up with four. I would have liked to have five to round it out nicely, but I’ll have to rely on you for that.