Tldr

From Mario Fan Games Galaxy Wiki

TLDR is an abbreviation for the phrase "<the post is> too long, <so I> didn't read <it>".

This is often the reply to long posts in the Pointless Post Palace or Arts Board. Needless to say, it offers nothing to the board and only wastes screen space.

It has been theorised that the abbreviation originated on the SomethingAwful forums, where it was attempted to abbreviate it even further to "~". Unfortunately, that is a tilde, not a "tildr", and this attempt is in vain.