I don't know, title says it all? Also, note that the following list will be heavily opinionated.
2011:
February 2011-December 2011 (Fresh Start, New Joinings): The Forum began a fresh community. A few users flocked in, and quite a few are still here. The Forum was the most peaceful at this time, with no hackers and trolls.
2012:
Need help from users.
2013:
January-March 2013 (Fan Games, Fan Art): This was a calm time of the Forum. Fan games and fan art had reached their peak in popularity. Many users supported the new fan games to become real games, and everyone loved some good ol' fan art.
July-August 2013 (Tootsicle Wave): The Forum fell into despair as the so-called 'tootsicles' joined. pickleric, the most infamous, was surprisingly the one who broke the least guidelines. Sweedsweerse and a few others were despicable, and they posted links to horrible websites. Everyone dreads this time.
September-December 2013 (KCP, Hyperposting Era): Although school began, the Forum only became more active. KCP fueled new users to join, and hyperposting struck the Forum. Suddenly, everyone was posting, posting, and posting! This caused outbreaks of spam, however, as you may imagine.
2014:
Need help from users for <July.
April-Early July 2014 (TWG, Calmness): As the hyperposting era came to an end, new calmness came to the Forum, a sensation which had not been felt for a while. TWG started, and became very popular. To this day, the Forum still enjoys a good game of TWG.
Mid-July-Late August 2014 (Arguing, August Shipping Wars): Once school ended, arguing returned to the Forum. For most of July, people argued over dumb reasons and the Shoutbox was a hotspot for this. The August Shipping Wars lasted for over 2/3 of August. During this era, the Forum was a battleground of arguments over very dumb subjects. Many users argued over shippings, and the fight tried to be quelled. Toward the last week of August, this incident died down and everything calmed down in time for school. This was also a spammy time, as in the last week of August the so-called "Posting Challenge" caused spam in over 3 boards.
September-Early November 2014 (Calmness): As school began, people got caught up with homework. The arguing on the Forum died down, and it was relatively calm. Hyperposting also died down, and only 2-4 users regularly hyperposted.
Mid-November-Mid-December 2014 (Hyperposting Returns): In the middle of November, hyperposting returned, but in a smaller form. Only 4 users hyperposted, but in total it added up to a lot. The Forum was still relatively calm during this short era.
Late December-Early January 2014 (Hyperposting Madness, Arguing): Once school ended for the holidays, hyperposting became more common. For the first week, the Forum still managed to stay calm. But in the last week of December fights broke out. People gave the password to their account, and spam flooded every board. On December 30, the situation got so bad, users were forced to lock their topics so spam could not get in. On New Year's Eve, people petitioned to remove post count. This split the Forum into two sides, since post count was an integral part of the Forum.
2015:
Mid-January-March (Calming Down, Town of Salem): School returned, and the Forum slowly calmed down. Hyperposting slowly died down, in favour of Town of Salem, which took the Forum by a storm. Users such as Sweedsweerse and pickleric returned, causing a few arguments, but they didn't last long.
April-June (Inactivity, New Users): Needs info, I was semi-active for most this.
July-August (Gore, Arguments): Once again, school ends and the forum plunges into despair. This time, two users (Papl and SaucyKing) spammed gore all over the forum and caused it to fall into chaos as everyone tried to find who it is. In the meantime, many users left. There were also a lot of arguments over small subjects, such as being places low in a user ranking and shipping (Shahzoda was fought over by 3 of his shippers). Eventually, the goreposters were found and the forum tried to calm down.
Two becuase i wasn't involed with them but wanted to stop ebby from behaving like that