Lack of thread is bad. If you don't know this, don't pick it up if you want something light. There is comedy and such, but the main aspects are plain serious. It's magnificently done though.
If you get hooked, enjoy joining the ranks of waiting for the next volume (the last one has only recently been published and only scanlated the last week in its entirety). It's not fun.
I had marathoned volume 1 through 8 when I'd only discovered it (already was a big fan of Asano Inio's Nijigahara Holographs, Solanin and particularly What a Wonderful World which introduced me to this fabulous mangaka) and it was one of the most important (relating/mindfucks/etc) experiences I've had from only a manga.
So Volume 9, all I can say to keep it short is: god damnit Asano ;A; This is continuing to redefine my take on what I previously considered as masterpieces due to too many things.
I see it as one of those mangas you should really try if you're into seinen, due to its unique aspects and storytelling. You can't really compare it to other works. You definitively recognize that it's done by the same mangaka as the other 3 titles I've cited but this one does differ in its own way imo.

Dead or Alive Ero-SFM Doubly Dirty
Flying Witch “Cute But Boring…”
Goddess of 2ch “Another Bathing Beauty!”
Phantasy Star Online 2 Phantastic: “What About the West!?”
Shounen Maid “A Fujoshi Delight”