Another reason I like it is for the lids on the little cartons. Some of them have cute messages. Some explain how to fold the foil into a spoon, which is really useful if you're packing these things on a trip. (Yes, I tried it. Yes, it works adequately.) But the really cool thing is that some of these have a white patch for writing messages. This matters.
One relationship model describes five love languages, one of which is words of affirmation. Among the easier and more effective expressions of affection in this mode is sending notes. People who have this love language naturally think of this, and will do it spontaneously. People of another love language generally don't -- but they may get the idea if presented with a product which suggests it.
What Annie's has done is take a product used in many families, and put a little value-added tidbit on top that encourages people to express their fondness for each other. Or you could use it to post reminders like "School out at 1:30." It's a family skill; it's a coping skill. It makes a product more useful, and it subtly hints people toward something they might not have thought about otherwise. It puts the bottom rungs on the ladder.
Things like this are ubiquitous in Terramagne. That makes it easier for people to acquire new skills or techniques. It's much less common here, but some of the more intelligent and prosocial companies do these things in L-America. Just seeing it makes me smile, even though I'm only buying this yogurt for myself. I'm not much given to sending notes in food, but I can do it when prompted if it's appropriate. It's a little bit of extra support that makes life sunnier, which makes me happy.
Because you get what you support.