Great read, like most other articles by Nir! Really insightful :)

What strikes me about Facebook is that it doesn't provide the emotion -- its layouts are uncreative and its colors are dull.

Instead, Facebook's users provide the emotion through photos and chat.

When a person gets tagged in a photo, it creates a trigger reaction and feedback loop that brings the tagged person back to the site.

Users create emotion; the product just doesn't get in the way.

It turns out it's really, really hard to make a product that encourages users to provide the emotion without getting in the way.

That's why there's only one Facebook. (Well, that plus network effects...)

Nir had another post recently that discussed emotional triggers:

Feedback loops and desire engines work best when users move quickly from trigger to action. The less time spent between feeling an urge and satisfying it, the stronger the habit.

Read more: http://www.nirandfar.com/2012/05/strange-sex-habits-of-silicon-valley.html

He's right. Just postponing increases willpower:

http://www.bakadesuyo.com/15-research-based-secrets-to-bulletproof-will

Purely from a self-motivated standpoint, if I wanted to make PandaWhale more addictive I'd need to squash peoples' postponement and fuel their desire to return with positive feedback loops, right?

Yeah. Throw in an intermittent reward system and create a leveling up system with unlockable bonuses/features and you're on your way.