Facebook's new Slingshot mobile app, just released today, is supposed to rival Snapchat, which is why Slingshot imitates Snapchat's impermanence: whatever messages you send via Snapchat will disappear a few seconds after they're seen, making it more like an ordinary, low-tech, non-recorded conversation.
Presumably, anything you send via Slingshot will soon vanish too. But Slingshot offers an odd new wrinkle: forced reciprocity. In Slingshot, if someone sends you a video or photo, you know it's there but are not allowed to see it until you send one of your own.
Slingshot's developers explained their rationale in their blog post announcing the release:
With Slingshot, we wanted to build something where everybody is a creator and nobody is just a spectator. When everyone participates, there’s less pressure, more creativity and even the little things in life can turn into awesome shared experiences. …
To get started on Slingshot, shoot a photo or video. It can be what you’re up to, who you’re with or a quick selfie. Add some text and color, then sling it to a bunch of friends. Here’s the deal: friends won’t be able to see your shot until they sling something back to you. They can then reply with a reaction—or simply swipe your shot away.
If any Slingshot developers are reading this, here's a free profit-building tip: you'd get millions of eager customers signing on to your service in nanoseconds, if you tweak your software enough that the whole forced-reciprocity thing applies not to video messages from friends, but email messages from spammers — you can't see any spam unless you send the spammers a message first.