I don't know that On Think Tanks would describe what it was doing using quite these terms. And, indeed, there are some important differences. Outputs from digital gardens are meant to be timeless (that is, often published without a specific date), connected via curation rather than ordered into a stream, and continually updated.
OTT made use of more traditional blog posts and social media posts—all of which are dated, ordered by chronology, and fixed once published.
That said, both approaches share the core idea of public thinking/public learning. The underlying ethos is identical, even if the toolsets are not.
We @onthinktanks have tried this with an evaluation for @Hewlett_Found @oso (as much as is possible with evaluations) https://t.co/05VjLHAJD1 but I would argue that some think tanks do this already through commentary, events, media presence, etc.
— Enrique Mendizabal (@QQMendizabal) July 4, 2021