It's like a write-in where anyone who wants to jumps into a Writers Feed Pad, Rise-up pad, or other shared writing pad link and writes poems - often guided by a prompt. Sometimes they're planned in advance and advertised around the site, sometimes they're spontaneous.
What's a Shared Writing Pad?
It just looks like a document except everyone is assigned colors - ask whoever opened the pad what the language/content rules are if you're unsure - but poetry jams are normally pretty clean. If you're uncomfortable with anything let the owner of the pad or a moderator know. Also if it's on Writers Feed Pad all YWS Rules apply in the chat meaning keep it family friendly and respect all requests and warnings from moderators.
A few general suggestions for writing in these pads is if your work has mature themes put a content warning at the top of where you're writing and don't delete other people's work without asking if you're not the person who started the jam or write-in.
Who can participate?
Well you! Just log on with your YWS username and password if it's a WFP, and you can join, doesn't matter if you weren't "invited" or have never been to one before - if you want to check it out, that's perfectly fine - no poetry experience or special invite needed. People normally identify themselves with their username, so you should see some familiar usernames on the top right-side of the screen.
Can I host one myself?
Yep! If you're interested in hosting a poetry jam - you can! It might seem like it's often moderators hosting these, but if you have a prompt you want to try yourself with some other folks - go for it! Post over in the Poetry Jam Club or the I'm Writing, Come Join Me thread and see who shows up - the same goes for poetry workshops - if you feel like you need help or tips - reach out to anyone in the Poetry Crew or another moderator like myself, and we can give you some tips. But really if you're interested, my advice is just try it out, see what happens.
Poetry Jams and Write-Ins can be a fun way to meet other users and get to know people and their writing a little bit more than you're able to just by reading works or following the People Tab - it also allows for immediate feedback and collaboration, so they can be great fun!
Good luck! Happy Writing!