Letterhack describes a fan who is regularly published in comic book letter columns.
Many letterhacks became well-known throughout the industry by virtue of their letters. Writer Mark Engblom describes the phenomenon this way:
“Chosen by the title’s editor (or, in some cases, the writer), a few lucky fans would get the opportunity to share their opinion with not only the creators, but a captive audience of fellow fans as well. In fact, some of the most prolific fans had letters printed almost every month in a variety of titles, becoming minor celebrities in their own right”.
Letterhack on Wikipedia.