Simply add up to 10 locations that you enter and leave often, and Instapaper will frequently update without manually launching it.
What a clever hack, this should make an already great app even better. I had never heard of this, but Arment says this idea is from News.me — credit where credit is due.
I also love this little privacy note:
Instapaper stores these locations only within the app itself, only for this purpose, and does not share them or send them to any web service (not even its own servers). I respect your privacy.