I was struck by the huge potential impact of this idea from Marcel van Remmerden:

Here is a simple but efficient way to spot Enterprise Software ideas — just look at what Excel sheets are being circulated over emails inside any organization. Every single Excel sheet is a billion-dollar enterprise software business waiting to happen.
I searched "google sheet" education and "google sheet" learning on Twitter just now and, within about 30 seconds found:

Google Sheet example 1

…and:

Google Sheet example 2

…and:

Google Sheet example 3

These are all examples of things that could (and perhaps should) be simple web apps.In the article, van Remmerden explains how he created a website based on someone else’s Google Sheet (with full attribution) and started generating revenue.

It’s a little-known fact outside the world of developers that Google Sheets can serve as a very simple database for web applications. So if you’ve got an awkward web-based spreadsheet that’s being used by lots of people in your organisation, maybe it’s time to productise it?

Source: Marcel van Remmerden