In this context, you can see the blockchain as a database, always available, and containing entries (transactions in blocks) that you can not delete. It’s very simplified, see the Wikipedia article [1] for more details about blockchain systems.
The specific features that I find interesting to build an “open trust system” built on top of it, compared to a traditional database, are:
- Transparency: anyone can explore this database, and verify that the software is using it in a transparent way. It might sound not important for something like Uber, but if you build an open trust system that could be used by different services, it becomes very important for authors (Uber, Lyft, etc.) to trust this system.
- Reliability: because a blockchain is distributed, it is always running and available.
- Trust: transactions are immutable and a transaction can not be falsified once confirmed (validated).