I'll get this joke when the missus buys me the book for Christmas. Meanwhile...
Dilbert: I was thinking of making a Android phone with a 4.65inch screen
Boss: That's not a phone, it's a tablet. Make is smaller. We are not made of LCDs!
Same as above :-)
I didn't get at first because I (and everyone reading it here) are looking at the comic on a computer monitor (which is not made of ink either). Maybe, Scott, knowing this realized had a hidden double-entendre for the web version.