Invalid
 

If one opens a title in any of the subjects and there is a statement about the post being invalid......what does that mean.....was it spam or inappropriate or what? Just curious

It is because for some reason the post was removed by the moderators. It may have violated the rules !

An Invalid Thread is one that has either been:
-moved and the redirect has expired;
-merged and the redirect has expired; or
-deleted because it did not comply with policy

A closed thread is one that remains visible but can’t have new comments added.