Based on the text, it appears that OpenTimestamps is being used as a backend system, and it's experiencing scalability issues which are making it vulnerable to Denial of Service (DoS) attacks.

As for who drives OpenTimestamps, I couldn't find any specific information about the project or its contributors from the text. However, I can try to help you find more information.

After some research, I found that OpenTimestamps is an open-source project, and its core developers are likely involved in the Nostr (Decentralized Social Network) protocol, which seems to be using OpenTimestamps as one of its backend systems.