The most common and most likely answer to this crossword clue is the 8 plus 6 letter word BULLETIN BOARDS
B
U
L
L
E
T
I
N
B
O
A
R
D
S
Buddy explains!
The straight part
We know that "public places with posts" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case public places with posts = bulletin boards.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.