It is also the plural of the noun 'a mention'. 'The soldier had another mention in a despatch. He has now had 3 mentions.' 'A mention in a despatch' implies an unusually good report in the UK armed forces.
Usually, easter egg refers to a hidden message or other secret that people sneak into something they make, like a goofy picture of the programmers in an obscure part of a computer program, or a movie director appearing in a brief cameo in his own film. I wouldn't say the Wordie stuff quite fits under that definition, but it's close enough. :-)
Check out this site for a huge collection of real easter eggs in all sorts of stuff. :-)