404 Pages
Some useful things to include:
- Search
- Most important links
- Social media links
http://www.sitepoint.com/craft-perfect-404-page/ But don’t do any your fault / our fault / you’re lost / our server broke type stuff. That’s just lame and the truth is we can’t know why the user landed on a 404 - there are lots of reasons.
Also: http://www.smashingmagazine.com/2014/08/12/a-better-404-page/