Thank you everyone for your comments.
QUOTE(watisthis @ Jan 24 2015, 06:10)

A ton of reasons. Most of it because of probability. Mine's been like 300~ for the past year or 2, and appeared 16 times.
Just wait, as more people post their battles, the chances of your monster getting posted increases. Just because your monster is around that level, just INCREASES the chances of it getting posted, doesn't mean you're guaranteed.
Just think of it as buying thousands of ticket every single day for months. You have a pretty good chance of winning, but you're still have a chance of losing. That's your monster.
My monster was about
250 a year ago, slowly leveling to its current powerlevel 576. 0 appearances. So, it still looks like she’s very unlucky.
QUOTE(Ichy @ Jan 24 2015, 06:49)

Maybe it has a name no one remembers?
Or maybe it is your low level mob has to share its place with 343435345345346 low level mobs?
If anything, I would rather assume that some people dislike my monster's name. But it seems, in “Events and Monster Battles, Just because” people usually don’t care about the names of the monsters involved. Like 80% of the posted parts of battle logs are just endings of a battles including drops and “You are Victorious!”.
I considered the possibility that the relatively low level is the problem, but then see what Watisthis just posted…
QUOTE(VriskaSerket @ Jan 24 2015, 15:47)

almost daily posted.
just feed another 100 mil to your monsters (IMG:[
invalid]
style_emoticons/default/rolleyes.gif)
I’m not sure what you mean… Should I just up monster’s level for better chances?
...
Well, in the end it's not like my life depends on it. As they say, "Unlucky at gambling, lucky in love." ( I wish, it was true >.> )