One of them has finally been given a name: Advantage and Disadvantage, thanks to the latest release of Dungeons & Dragons. My first published use of this rule was in the Fudge Dungeon Crawl article I wrote for the now defunct Fudge Factor e-zine, having been published there on May 2, 2005 (check under the Treasure heading to see it in its infancy), but I'd talked about it numerous times on the old Fudge e-mail list prior to that.
Basically, it works out like this: if you have Advantage on a roll, you ignore a minus result ("-" on Fudge dice; 1 or 2 on d6s). Conversely, if you have Disadvantage on a roll, you ignore a plus result ("+" on Fudge dice; 5 or 6 on d6s). Unlike my house rule's namesake, you can have multiple levels of Advantage or Disadvantage (a character with Advantage 2 on a roll would ignore two minus results, for instance) although that should be rare.
Disadvantage will cancel Advantage and vice-versa. In the rare case that a character has multiple levels of one or t'other, whichever remains after the maximum equal amount is canceled from both is what is applied; so if a character had two levels of Disadvantage and one of Advantage, his next roll would be made with Disadvantage (one level of Advantage cancels one level of Disadvantage, leaving one level of Disadvantage remaining).
The reason for this house rule is that a +/-1 modifier in Fudge is a huge jump; it's 14% of the entire spread. That would be like getting a +3 modifier in d20, or a +2 modifier in GURPS. With these Advantage and Disadvantage rules you can give a character a boost (or penalty) without it being so impactful.
I think you could just as easily use Advantage and Disadvantage in Fate, as well.
