Lots of players and Storytellers record the events of game sessions. You can read thousands of actual play write-ups online. Indeed, many gaming forums have entire sub-forums dedicated solely to posting session summaries.
Why are session summaries useful? They can seem indulgent, whether because you’re tying down stories to a page when the real fun lies in playing them out, or because you’re seeking acclaim from readers online. But they serve a useful purpose for your play group.
Session summaries help the Storyteller and the players remember what’s happened in the game. After a while, it’s easy to lose track of plot threads and minor characters—What was the name of that random guardsman who’s marrying the Dawn’s daughter? Which parts of the ruined manse did the PCs explore? Where exactly did the Twilight stash the Soulbreaker Orb during Limit Break?
Worse, without a record of events, the Storyteller can misremember key plot points, only to realize that she’s painted herself into a corner once everyone involved pools their recollections, revealing that characters have acted uncharacteristically or progressed with schemes that make no sense once the full context of events is recalled—Why did the Mask of Winters let the Circle pass through Thorns without confiscating the jade casket he’d been hunting for the entire chronicle? Life in Great Forks has seemed normal for the past two sessions; shouldn’t it be full of refugees after the PCs burned Nexus to the ground three sessions ago? The Zenith’s demon hunter retainer finally Exalted as a Lunar a few sessions back; hey, I just remembered that she was actually a Dragon-Blood in disguise! Working your way out of a jam like this can lead to some really cool plot twists and entertaining storytelling, but it risks breaking immersion for Storyteller and players alike.
Aside from all that, summaries provide a shared context for play. It’s kind of like how, once you see the movie version of a book, you tend to visualize the book character as the actor from the movie. But where book readers maintain their own private visions, RPG players share an imaginary space with the rest of the group. If everyone reads the session summaries, the shared imaginary space gains texture and solidity as every player remembers events through the filter of the summaries’ writer.
This last reason is good cause to go the extra mile and elaborate on the story with sensory and cultural detail that wasn’t necessarily spelled out during actual play—What does the architecture look like here? What sort of clothing do people wear; what food do they eat? How do people greet one another? In what regard do they hold their rulers, their cosmopolitan kin in the capital, or foreigners who’ve settled in their lands? If the players are reading the summaries, they’ll soak up setting information there that they might not otherwise be aware of. This will make the setting feel more real and help ensure that everyone’s on the same page in terms of how the setting works and where the PCs fit into it.
Of course, there are limits to the utility of session summaries. Taking notes on what happened in the session shouldn’t be allowed to interfere with involvement in actual play, and a Storyteller with limited leisure time (which is just about every Storyteller!) should prioritize preparation for the next session over writing up the events of the previous one. But beyond these obvious issues, I think the value of session summaries is clear. Share your gaming experiences with your players—and after that, why not with the world?