A Stupid Message can be found from
- a private message
- member's house
- wiki page
- any other place
A Stupid Message tells you to
- re-post it somewhere
- send it to someone
A Stupid Message often
- tells a story of some kind
- talks about a serious/funny/cute thing
- is annoying
- is something you've seen/received already many times
To say it clearly, Stupid Message is a message that's stupid.