Obviously the meaning is publicly accessible and searchable archive. Those don’t qualify.

SafwatHalaby:
Non public
You can view messages in a browser without registration if you copy the link to it. Channels can be viewed in full, without a link to a separate message.
I was not aware of this. Can you provide a link to demonstrate?

SafwatHalaby:
Proprietary / not open source
All clients have an open code. Only the server part is closed.
The server being proprietary is itself a problem for many people, for many reasons. I’d rather not get into a discussion as to why.

SafwatHalaby:
Non threaded
You can configure topics. But I don’t recommend doing this if you don’t have a chat for several thousand people or if you have hundreds of messages a day. It is better to use Reply when communicating in a chat. This way you can view the entire thread via the context menu
So you agree that it’s impractical to have threaded discussions on Telegram.