The most common and most likely answer to this crossword clue is the 7 letter word VLOGGER
V
L
O
G
G
E
R
More clues leading to the result VLOGGER
Buddy explains!

The straight part
We know that "One publishes online" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one publishes online = vlogger.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does VLOGGER mean?
VLOGGER noun- A contributor to a vlog.