I think that it would be a good idea to have a date, "month, day, year", posted on all posts. Perhaps, continue how long ago a post was made as well.
I, also, think that for how long something was posted, it would be better to post "years, months, days". This, would perhaps use a routine where 30 days would be counted as a month for the first 11 months, which would be 330 days, then, for the 12th month, after 35 days, make that count for a year. That would be 365 days for a year. After a year's time, then just stop counting at that point and say that the post was made over a year ago, and stop counting after that point.
I don't know the plan for archiving. It could be that after maybe 2 years, a post would be archived in a non-active storage area or just eliminated. I would think that the decision to archive something could be something for organizers to decide.