Instagram's monthly users have reached the 1 billion mark moving up from a total of 800 million monthly users as of September of 2017, which means that in ten months Instagram gained a total of 200 million monthly active users. This highlights not only Instagram's continued growth but also its continued popularity, especially considering its daily active user count (500 million) which is already at half of the number of users which are logging into the service on a monthly basis.
This also seems to be Instagram's largest point of growth in regards to monthly active users, as all other reported growth points since the app's launch seem to be around 50 million to 100 million from a previous count, though worth noting is that many of those reported segments of monthly user increases include a gap of five months and not ten. Still, there are a couple of points where Instagram jumped 100 million in number for monthly users after about nine to ten months, which certainly appears to suggest that Instagram is becoming more popular then it was in year's past, which is likely due in some part to its eventual sale to Facebook who has been spending time and money to improve the service and app with plenty of feature additions and changes.
Though Instagram has made plenty of improvements in the past six to twelve months already which its new crop of monthly users will be able to take advantage of, such as adding the ability to shop through Instagram Stories instead of just in regular posts, it's also launching a new video service/feature called IGTV that will let users upload hour-long videos to the Instagram platform, which is sure to draw some attention from those new monthly users as well as existing ones. Whether or not it will directly increase its monthly users to an even higher number is unclear but that is also a possibility.