A fork of Rural Dictionary
Too long, don't read
or
Too long, didn't read
A post, comment and/or reply that is (perhaps) gratuitously, (over)indulgently long.
.... and so A happened to B, and C got the bad end if it really, but it's not as simple as that...
tl; dr
(expounding of above point)
OR
...omg, sorry but, tl; dr! :) I *do* agree with what you said about Y being in front of Z, though...