Was it Dave Weiner? Ranjit Bhatnagar? Montaigne?
Julius Caesar, perhaps?
Scott Rosenberg, author of say everything, says the qeust for the first blogger is, in the end, an infinite recursion; each candidate a pointer to one before. And the search is as futile as searching for the first poet, first playwright, first novelist, or even the first human being.
“Blogging evolved, just like human beings have evolved. And the question is not who was the first blogger, but how did we get here.”