Once upon a time, Instagram was just for sharing photos, mostly of food.
But over the past year or so, the app greatly expanded in functionality. Live streaming is now supported, multi-photo posts have been added, and the app now has Snapchat-like disappearing photos and videos.
Back in August, Instagram cloned Snapchat's 'Stories' feature, allowing users to post short snippets of their activity that disappear after 24 hours. In a post about new stickers, Instagram revealed that over 200 million people use the Stories feature every day. Engadget pointed out that Snapchat only reported 158 million users in its IPO filing in February, meaning Instagram Stories has more active users than Snapchat.
This should be good news for both Instagram and Snapchat users. Instagram will certainly continue to make the feature better, and maybe Snapchat will become motivated to fix the buggy Android app (like they keep saying they will do).