Typically, RP games have at least two comms: one for IC interaction (usually split into two or more; e.g. one comm for prose/action logs, one comm for "network" interaction if the game setting allows for that kind of communication) and one for OOC coordination. Many RPs have separate comms for memes and fanwork, too.

Character journals are used to post to these comms, and if the format of the RP allows for it, they may be used as personal communication devices for the characters as well. A character's info/RP application is often posted to the journal, for ease of finding contact information and character details; for many, it's also considered a courtesy to have an anon-enabled feedback/"How's My Driving?" post too, although it's by no means mandatory for a lot of RP games.

As for events/storyline... It depends a lot on how the RP is being run and what the premise is. Apart from player-run plots, many RPs have all sorts of game-wide events, ranging from out-of-the-blue temporary curse events to events that span a longer period time and are incorporated into a story arc. Players react to these events through first-person posts (to the network or their journals), third-person logs, or a mix of both.

Some DW RPs you may want to look at to see what I mean: paperkey, pandoras, gateway_rp.