A publon is a "quantum" of publication. It is the least publishable unit of research.
I have found this to be a very helpful concept in doing and supervising research and deciding what and when to publish. The basic idea is that once you have a result that is publishable [a new equation or measurement or graph or numerical result] for a specific research project one should start to prepare a paper around it. Large projects can be broken down into publons. I first really took on board the concept after reading Peter Feibelman's A Ph.D is not enough.
The advantages are
-research and publication can much more manageable
-it avoids procrastination, particularly by perfectionists who always want to get one more result...
-it placates the "bean counters" who expect quick results and large numbers of papers
-papers should have a single message and not several. publons prevent that single message being diluted or distracted from
-it can be helpful in building confidence and momentum in new situations: a new project, a new institution, a new position, a new student, or a new postdoc....
The disadvantages/dangers are
-results are published too quickly before they have been checked, compared to other methods, or for other systems.
-peoples publication list becomes inflated.
-too many short and superficial papers are published
-it is pandering to the "bean counters".