Telegram is the favorite messaging app of ISIS.
Telegram is a secure messaging app which sends messages that are fully encrypted, can self-destruct (like Snapchat), and are almost impossible to spy on. This makes Telegram great for anyone who wants to hide their chats from the government — including ISIS, which has instructed its followers to use the app.
Yik Yak is an anonymous app that's been used for cyberbullying.
Yik Yak is a popular anonymous bulletin board of sorts where people can post what's going on around them without worrying people discovering who they are. Of course, the anonymous nature of the app has led to some abusing the app and cyberbullying, including a run of recent racist postings around university campuses.
The League is Tinder for "successful" people.
The League is a selective dating app that only allows certain users in. Most of its users are wealthy or attended Ivy League schools, and you only get access if the app's algorithm decides you're cool and successful enough.
Price: Free (iOS)
1Blocker lets you block ads on your iPhone.
Ever since Apple decided to allow "ad blockers" on iPhones, a debate has continued about whether they are ethical. These apps let people block ads on Apple's mobile web browser. Opponents say giving people this power is destructive to websites that rely on advertising revenue to stay in business, while supporters say the apps fix a fundamentally broken mobile web experience.
Price: Free, with $2.99 "Pro" version (iOS)
Ashley Madison wants you to have an affair.
Ashley Madison encourages its married users to cheat, allowing people to search for married people nearby who are also looking for a fling. It burst into the national spotlight earlier this year when 32 million of its accounts were compromised by hackers, starting a lot of uncomfortable conversations between would-be cheaters and their spouses.
Wikileaks lets you browse leaked documents and files.
Apple removed the Wikileaks app from the App Store, but you can download aversion of the app on Google Play (though it hasn't been updated in years). The app lets you browse and dive into Wikileaks' treasure trove of leaked documents.
Price: Free (Android)
After School was pulled from the App Store but has since returned.
After School is an app designed to give high school students a place to discuss things anonymously without worrying about a teacher or parent finding out. It was pulled from the App Store after kids started using it for bullying, but After School has since returned with new safety features.
Price: Free (iOS)
Tinder was the first app that made it popular to be shallow.
Tinder blazed the trail for people to hook up based solely on looks alone. It used to only show you the photos and first name of other users, but now lets you add your job and education. However, the core experience is still swiping left and right until you find a match that also found you attractive.
This post is an update of a previous one by Steven Tweedie.