So, I'm in love with Dungeon World, but I have a quick question about forwards. Do they stack? The +1 suggests that they do, but I just want to be sure.
"Stacking" is a concept that is not touched very much upon. Searching through the PDF, the only place it shows up is on page 327:
n Armor: It protects you from harm and absorbs damage. When you take damage, subtract your armor from the total. If you have more than one item with n Armor, only the highest value counts.
+n Armor: It protects you and stacks with other armor. Add its value to your total armor.
Bold font added for emphasis. Here, it is mentioned that +n Armor stacks with your highest n Armor item/rule/whatever.
Now, why is this relevant to your question? On page 21, the rules explanation for take +n forward reads:
...Say “take +1 forward.” That means to take +1 to your next move roll (not damage). The bonus can be greater than +1, or even a penalty, like -1. There also might be a condition, such as “take +1 forward to hack and slash,” in which case the bonus applies only to the next time you roll hack and slash, not any other move.
The issue of stacking is not mentioned here at all. The bonus is applied to your next (relevant) roll, no matter what.
In conclusion, yes. Bonuses stacks, unless otherwise stated in the rules. As an example of when two seperate bonuses doesn't stack, look on page 72, at the bottom of the page dedicated to the move Aid or Interfere:
No matter how many people aid or interfere with a given roll, the target only gets the +1 or -2 once. Even if a whole party of adventurers aid in attacking an ogre, the one who makes the final attack only gets +1.