Actually removing dates would be a good idea salone and allow me to add to that. So instead of posts saying the exact date, why not change them to words like
"Recently, Not Too Long Ago, A While Ago, Sometime Ago, and Ancient Times."
So Instead of seeing: "Posted 11/15/2015 12am." It would say "Posted Recently."
Keep ancient as a title for something like a year or two old post.
Figure out the times, but just don't let users know the time differences between the words. Admins/Mods can read them as the proper time if they wanted to.
A part of me also wants to remove the see who's online part as well. Seeing that no one is on can quickly have someone leave instead of posting once or twice. What's important is that someone attempts to post even once. But this idea I'm not too sure on, depends on everyone else.
But I still don't think just for posting should there be additional awards, thread making yes. But like you said that might encourage people to only care about their threads. But wouldn't that also mean they have to attract other people as well? Running charities, market threads, art shops, and so on.
The only thing close to additional awards I can agree with is a reward system for posting at least once (or five, whichever) daily (with a considerable amount of word length) and that's it. With rewards getting higher to a max of a week, but every day you long in after that continues to give you the max week bonus as long you log in and post once a day. What the rewards can be? Dunno. Aurum, random commons, maybe a RIG that gives out multiple commons, extremely small chance for like 10 runes (only when you have a 7 day bonus going on)? Maybe a chance for a reward system exclusive RIG with it's own prize pool as well that has a chance to appear after like day 3+ ( Odds slightly increase each day maxing out at 7+) A RIG behind a RIG, but that's mostly just to prevent too many people getting the RIG too fast, you want it to be stretched out a bit. (You might even add items to those RIG's as well.)
Oh and Pyramid scheme tactics? That's.. Sort of hard to accomplish. People can easily make mules and say they had referral them, then post with both accounts to redeem any exclusive/extravagant reward. The only thing I can think of is to have it so if someone invites someone they get like 5% or less of the aurum that person makes when posting on Trisphee if they inserted that persons name when joined, short term that is a nice motivation, but long term someone could had been successful and invited like 1,000 people to the site and be making way too much aurum inflating the system (granted we have a ton of aurum sinks with the shops, and more could always be made.) And getting 1,000 new players for one account would be impressive on it's own right, and probably deserves that aurum for bringing in that many people. <-- Only way I see a referral system working.
I have also suggested in a past to bring back referral contests and you could pull a Scrimshaw and provide a exclusive reward to anyone who participates and gets at least 1 person to join Trisphee with at least 10-15 posts. (You can check to see if it's a mule as well.) This way it's more micro-mangable manageable to snuff up users who are lying for the exclusive award during the contest time period then it would be to have it open ended and people could be abusing this at anytime of day.
But still I don't think additional posting rewards would be good in the long run. Maybe, and I mean just maybe have a charge meter, and once a person types a considerable amount and have that charge reach 100% they get some sort of time bonus (like 5-10 minutes0, like they have more luck in games, maybe a small aurum boost, when the wonder trade is completely up, they have a chance at getting a uncommon for a common, or rare for a uncommon. But that's pretty stretching it, and some things would have to be monitored and so on.
I can keep coming up with ideas, but other then the refer ideas and date posted. I really don't like bringing up ideas based on a system like this. :/ I'll keep thinking about it though.
edit: While my head and note card drawer of ideas for Trisphee is open other ideas:
A avatar contest system based on thumbs up and thumbs downs only, people entering the contest can only thumb up other submissions or ignore them, but cannot thumbs down. Winning avatars featured on front page.
Announcement icon, and on front page a list of recent announcements.
Storing other avatars into a save system (this was brought up before) so you can have multiple avatars/outfits saved. It costs 10 runes for additional avatar saves, but give people a starting number of 2-3 save spots.
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Game where you can save any image as your pet (so like take Trisphee items, save a single image of those animals, and dispense them randomly. So think like most egg clicking games/signatures, but it's more straight forward, no evolutions, ect.), clicking on it to feed it and take care of it, and when maxed out you pet can be converted into prizes then resets to 0 clicks.
Oh look an old idea that can be re-purpose into a posting rewards, give random stat points for doing daily Trisphee tasks. +1 Str for posting 100 times or something. Then use those points and establish some sort of game that uses them. It could also be +1 to Posting or things not necessary the generic stat system. These could also be used for events, or even just roleplaying purposes with event forum based games based on them. (So like dungeons and dragons, with like Salone the dungeon master or something.) A lot of potential.
... I'll wait until I gets a reply on what's already written before coming up with more chizz.