When there's a rogue in your midst, particularly in random battlegrounds, and you're going about your merry way with a couple of cohorts nearby, they may not notice when you're suddenly sapped. SaySapped is a great little addon that does exactly what it says on the tin -- it makes your character say "Sapped". Simple as that! It's also very handy in rated battlegrounds, saves the use of the chat channel to announce such things, and allows your team to make a decision on whether to leave you as rogue-bait, or to stay and fight. Especially if there's two of you defending the flag or base, it's a boon.