maybe it should be variable?
-10% of the total number of replies
-display every Xth post
-display the first 5 posts then the last 5 posts
.
.
.

>>2
Some decent ideas, however I would personally be against any first X posts. Because people would be conscious of the fact that those key posts are going to be perpetually visible and they would try to fill them in with their opinions, bait, or shitposts all over the board even in threads they wouldn't otherwise post in at all.

>>3
>however I would personally be against any first X posts
So a list of threads like 2ch viewers or traditional forums?

Show five replies in random order.

Randomly select one of the suggestions here when the thread is created.

show the top/first five replies from the archived 4chan or reddit thread with the most similar OP title and body text.

Show a big sjis benis as a reply

Show a big ASCII penis as a reply.

sjis ibuki suika tiddies

show 7 random replies from the same board

show an ansi garfield face as a reply

>>12

.--.. .--..
/ # \/ # \ \
|# # #|# # #| \
,: ___; ___ | |
,~ / \/ \ ~`.
.,--.| | | ,.. #`.
: | * | * |' `. #:
|`. \___/\___/ ; :
: ~| ( ) /~ #
`# \ /~\ / |'
`. `--' `----' #/
\# .'
`-.. #/.
/# ~ ~~ #\