I posted my app Fresh Cards on Product Hunt a few days ago and got barely any interest, maybe 5 upvotes.
Last night I took a look and some random people upvoted it to 15 or so. Went to sleep and got up, and now this morning it's up to 50.
I'm not that familiar with how PH works, so this is kind of fun to see! Already got one person emailing me saying he can't find the app in the Chinese iOS App Store, so I have something I can fix up today. Exciting!