Now that I have gotten the legally required Canadian greeting out of the way, I can get around to introducing myself.
I've been using OP for about 2 months as a player in the Shadowrun campaign "Geek The Mage First":http://www.obsidianportal.com/campaigns/geek-the-mage-first playing the Mage of the party. Obviously, a good choice considering the title of the campaign. I've argued that since Sam Wolfe is a shaman rather than a mage he should't be geeked first, the men with guns typically haven't thought that argument carried merit. :)
I've definitely found that OP allows for some great player input in the running of a campaign by allowing players to easily add to the story. I'm always finding it interesting how different players at the same table can see very different storyline progressions. Of course this is even better when all this is being done from the character's point of view. In my opinion I think this is one of the best things OP does to improve any game, it helps the player/GM communication about the storyline at least from a player's perspective. I haven't used it as a GM yet, so my experience with OP in that way is limited, but the GM secrets seem to be useful for doing prep beforehand.
During a game I can see OP as being useful as an online reference to old NPCs and such. Does any one use it as more than that during a game? What are people's favorite applications for gaming? Personally, I love using RPGTool's Maptools and displaying it on the plasma TV and player's laptops for character movement. This is especially true with large or numerous maps.
They are among us!
XCom: Defiance - Campaign of the Month November 2016