Anyone can organize chess events on Lichess. Any user can organize an arena tournament, simultaneous exhibition or 2-player match, with or without prize money, promote it via social media, and stream the event on Twitch or YouTube. It is not required to involve Lichess staff in any way.
However, if you do contact us ahead of time, we may be able to help you in a number of ways.
1) Participation requirements: We can require that arena tournament participants must have a verified title, have a Lichess rating with a certain range, or have played a certain number of games on Lichess.
2) Promotion: We can promote your event on our social media accounts and on our front page. We can also schedule arena tournaments far in advance, while normal users can only schedule arena tournaments one hour in advance.
3) Moderation: If we know about your big event in advance, we can make an effort to distribute our moderation resources appropriately.
Just four months into 2018, we have seen some incredible events organized on Lichess to the benefit of players and spectators alike.
Since December 2017, Lichess has organized several big Lichess Titled Arena events (e.g. here, here, here and here) for titled players with thousands of dollars in prizes.
On many different occasions, LM Justin Tan (@JannLee) has organized and streamed Crazyhouse matches against GM Yasser Seirawan (@yasser-seirawan)