The Fabulous Pynch-o-Meter! (PDF)
I just whipped up a handy little line-gauge for Against the Day. You can download it, print it, and cut it out. The result will be a nice little device that lets you quickly determine which line to reference when commenting or reading others' comments.
Plus, it doubles as a bookmark! Sa-weet!
Later note: If you print the file from Acrobat Reader, remember to change the "Fit to Printer Margins" option to "None" under the "Page Scaling" pulldown. If you don't, the thing will print inaccurately. God, I hate computers.