I'm an early user of the app and I use it every day several times per day. It helps me save information forever. I have saved 1400 screenshots in 6 months using Screenple.
When I'm reading a book or a twitter thread and I find an interesting section of text, rather than using Kindle or other s highlighting functionality, I save the screen on Screenple. That has several benefits:
1) it's now stored with all other things on the Screenple search database
2) I can easily crop and share parts of the text
3) I can add a reminder so I can do something about it later on.
The reminders are very powerful and the reason I'm addicted to Screenple. It became a TODO app for me because I can create a very quick reminder no matter what context I am or what information I'm consuming.
It is much better than the official way to save screenshots. The crop feature is awesome!