Here Kaiser touches on the broader themes inherent in the concepts of atomic notes, which might be used to build up new and interesting structures. He doesn't specify the "size of a note" nor does he say that one will "know it when they see it", but he's suggesting something very close to it.

Rather than define the appropriate size, a feat which is difficult to do at best, he's providing a very narrow set of benefits for encouraging one to cut things down to size as they index them: small pieces are easier to use to build new things.

Catchwords (broad or even narrow topics) can be useful, but one should expand beyond these short words to full phrases or even sentences/paragraphs which contain atomic (or perhaps molecular) ideas that can be linked.

We could reframe the atomic as simple catchwords, and make molecular ideas combinations of these smaller atoms which form larger and fuller thoughts which can be linked and remixed with others.

Dennis Duncan (2022) touches on this in his book on Indexing when he looks at indexes which contained portions of their fuller text which were later removed and thereby collapsing context. Having these pieces added back in gave a fuller picture of ideas within an index. Connect this idea with his historical examples.

Great indexes go beyond the catchword to incorporate full ideas with additional context. To some extent this is what Luhmann was doing at larger scale compared to his commonplacing brethren who were operating far more closely to the catchword (tag) level. (Fortunately they held the context in their heads and were thus able to overcome some of the otherwise inherent problems.)

The development of all of this historically seems to follow the principle of small pieces loosely joined.

subjects cannot be described in terms of a strictly hierarchical order, it is rather a form of loose coupling insofar as one can find lower-level subjects which do not fit systematically to the top-level issue but show only marginally connections.

There is something suspiciously similar about the instantiation of a zettelkasten and the idea of small pieces loosely joined.

Perhaps also related to the idea of a small number of primitives which can interact in a small number of ways, but which gives rise to incredible complexity.

And this is almost exactly what the IndieWeb is.

Primarily I've been heartened to have meet a group of people who are still interested in and curious about exploring new methods of communication on the web!

I'll agree that there is no silver bullet, but one pattern I've noticed is that it's the "small pieces, loosely joined" that often have the greatest impact on the open web. Small pieces of technology that do something simple can often be extended or mixed with others to create a lot more innovation.