Filling in the history of Thedas in the Dragon Age Keep, I realise I really don't remember much about Dragon Age. I needed to consult Google just then to discover that the world it's set in is named Thedas, for example. Did I give an amulet to a beggar in Origins? Maybe. What's it to you? Who's Gascard and why did I kill him? Was Cullen the nice Templar or that mean one? Maybe I killed both.
Keep is the tool that BioWare are using to set up the state of the world in Dragon Age: Inquisition, building up a history of decisions your characters made in earlier games. And it's now in open beta.
Keep can't import saves, so you'll need to get your hands dirty to recreate or alter the world setup you fancy for Inquisition. Beyond basics like the Warden and Hawke's personal details, it has almost 140 events you can change, by my nasopharyngitis-addled count. These go from small things like how you treated a poorly deer and whether you killed... Danzig? (Bratmobile's Where Eagles Dare cover is amazing, by the way) to big ones like who saved the world and who you 'did it' with. I highly recommend having the Dragon Age Wiki open in a tab so you can check who these folks with dull names (Danzig aside, obvs) are, and what you did during their unmemorable quests.
And then you can watch a pretty cinematic with Varric narrating your personal history of the world.
"Not every choice will impact your playthrough of Dragon Age: Inquisition, however this means we can accommodate importing for future Dragon Age titles," BioWare say in the Keep FAQ. They note that they may add more options and choices to Keep over time.
Inquisition is due on November 21st. If you've ignored everything I've said and refuse to read words, here's a fluffy video which doesn't say much about Keep: