Here's a guide to how this all works on a cultural level:

Glossary

Comm - A comm is a community. Plural: comms.

F-locked - F-locking your journal means all your entries are only viewable by people you grant access to, that are on your access list. The 'f' stands for 'friend', because f-locking was a practise that originated on LJ, where access and subscribing were bundled under the term 'friending'. F-locking helps cut down on drama and harrassment by letting you talk to your access list or even specific access lists depending on how intimate a friend various people are.

Mod - moderator. Plural: mods.

Differences from Tumblr

- The people you subscribe to are on your Reading page. Anyone can see them. This is how you can make new friends! Go to a friend's reading page and see what comms they're in and who they follow!

- No more 'if you follow someone you automatically give them access to locked posts'. You control your privacy! Maybe you want to give someone access, but not read their journal; maybe you want to read someone's journal but not give them access just yet! Maybe you want to give them both! But you have choices, just like in real life, you don't have to treat privacy as an all-or-nothing game!

- Profile pages are complex and you can put custom html in there!

- Profile page has an interest list! Put your interests down and if they light up as a link, click them! That takes you to a list of users and comms that all have that interest too! Make friends! Join comms!

- There are no likes, no reblogs--your OP stays on YOUR journal, and people comment and talk to you and one another all in one spot! No more confusing chains, and everyone can see all the different threads and join in a real discussion! Again, make friends!

- You can post to a comm, which means you can separate your fandom stuff from everything else. This means boundaries are automatic and nobody has to see stuff they didn't sign up to see.

- Comms also centralise fandom activity--post your fic and art to the comm where it will be seen by fandom people!

- Tags are much shorter here, because we use them not to chatter but to categorise posts and make them easier to find (this is especially useful for comms, icon makers, etc). Colons create tag categories (example: 'character: sibby', 'pairing: sibby/rach').

- You can edit an entry and because there are no reblogs, the changes are immediately visible to everyone. For big edits, it's common practise to put 'ETA:' before your additions, and you can add a date/time if you're fancy.

- We have at mentions, but you can also link to other usernames on other sites with a special tag! You can find out how to do that here.

Practises

We have multiple icons (also called avatars), they are 100x100 and gifs are allowed!

- For courtesy and safety of photosensitive users, please don't make your icons flash quickly.

- You can pick a different icon for each journal entry. This can help give your journal entry or comment a 'tone', or you can have different icons for posting in different fandom comms.

- If you find an icon somewhere, it is common practise to put the maker's username in the description.

Extra features for entries!

- Every entry you can put a mood, location, and music. You can also change your journal theme to list these as different things! Go wild!

- You can customise the text. Have your comments be 'whispers' or 'squees', call your reading page whatever you want!

- Entries (and profiles) allow more html! You can put TABLES, you can fine-tune bold and italics (and colour). The cut tag actually works, and you can end it and put text AFTER it! Find out how here.

How to post fic here

- A header is nice, and you can make an easy one here

- Post your fic or art under a cut tag.

- Link to previous chapters if they're not all posted on an archive like AO3.

- Fancy people can make the link to AO3 look like a cut tag! That's a fun little thing you can do if you want.

How to Comm

- Comms tend to have moderators and rules. Rules are posted on the profile of the comm, and the usernames of moderators are as well.

- Comms can be f-locked too! And you can lock a post to a comm so that only members of that comm can see it, too.

- Comms can have open membership, or you can need to apply to join.

- Comms can have rules or not, but all comms have at least one moderator that created the comm in the first place.

- Comms can also have it set so they can have many people subscribing, but only certain people are allowed to post. This can be useful for comms that are a small group of writers that have agreed to post on a schedule (such as writing comms with weekly themes), or for communities where the mods post an entry that starts a discussion and most of the interaction goes in comments (such as news or comic scans comms).