This week, we’re bringing you the latest news from Instagram regarding their rapidly growing user base.

In addition, global ad revenue among social networks continues to accelerate. Finally, we take a look at the actual adoption of push notifications among app users that every mobile app advertiser should see.

Just nine months after Instagram announced its a user base of 300 million monthly active users, Instagram has reached a whole new level of popularity. Today the photo-sharing social channel totals over 400 million monthly active users. The chart above doesn’t do this overwhelming growth justice; not only has the number of users grown, but the global footprint as well. Of the recent user base addition, over half live in Europe and Asia. The highest adoption comes from Brazil, Japan, and Indonesia. Today, over 75% of all Instagram users live outside the US. This growth is great news for advertisers who now have the ability to fill Instagram feeds with more creative ads, both in photo and video format. If you haven’t gotten started advertising on Instagram with Social.com, now’s a great time to start!

Instagram isn’t the only ad channel growing rapidly. Today, total social networking ad revenues are accelerating at a rapid pace, according to eMarketer. Globally, ad spending will reach $25B this year, higher than forecasted April of this year at $23B. This is largely due to Facebook’s growth in ad revenue, reaching $16B globally this year, a staggering 42% jump from 2014. Instagram, the newest social channel to offer advertising, will be responsible for 5% of that Facebook spend, at $600M. It is estimated that in 2016, Instagram will reach $1.5B in ad revenue. In addition, Twitter will have a 62% jump in ad revenue from 2014 to 2015 and LinkedIn a 25% jump.

According to ComScore, 31% of smartphone users rarely or never accept push notifications from mobile apps. This is a big deal because push notifications have long been considered a crucial component of app success and audience engagement. Unfortunately, users do not respond well to this form of pop-up message. In fact 67% of users only accept these notifications sometimes to never. That is almost 70% of an apps total user base. For this reason, advertisers need to realize that just because a user has downloaded your app, they won’t necessarily be receptive to notifications. So what can app owners do to re-engage with users? App re-engagement ads on Facebook and Twitter are the solution to reaching users within the platform where they are spending time, without sending them a pop-up message that they are likely to turn down.

To learn about how TripIt, the highest-rated travel-organizing app, increased signups by 482% and decreased their CPA with the help of Social.com, check out our case study.