A story is said to be anecdotal if it makes a truth claim which has not been established scientifically.
An anecdotal example is one which has not been deduced from rigorous inquiry. An anecdote is informal, impermanent but potentially useful.
Anecdotes used to be even more useful when they meant what their name actually means: things which have not been published: unpublished stories. An-ek-dota: things which have not been given out.
Many unpublished things are true. Many unpublished works are better than those which have been published.
On the other hand, to be unpublished is to be unknown which is to struggle in the space between potentially useful and interesting and potentially harmful and fake.
Anecdotes don’t get published, they get disseminated. Unlike dissemination, publishing puts the anecdote publicly on trial for everyone to see, assess and adjudicate on. Dissemination inseminates, merely seeding and reseeding, without any concern for accuracy or responsibility. That doesn’t make it any less useful. Only more risky.
One of the spiciest medieval history books was the Secret History written by the Byzantine historian Procopius in the 550s AD. The History focuses on the Byzantine emperor Justinian and his wife Theodora. Though only discovered in the 17th century, it was known in the 10th as Anekdota, Procopius’ unpublished works. The History is truly anecdotal, peppered with scathing attacks against the imperial couple. It is anecdotal, but also left unpublished, which made some historians suggest that it was Procopius’ guarantee against the risk of being dragged down with the emperor in case of a conspiracy. The anecdotes would have allowed Procopius to prove his non-involvement in the regime. Useful stuff indeed, and a fantastic source for later historians.