APIs

Fitbit - Health

Groupon - Shopping

Google Analytics - Tools

We the People API - Messaging

Pinboard - Tools

bitly - Search

Bitbucket - Search

LinkedIn - Social

Foursquare Core API - Maps

Stack Exchange - Tools

DeployGate - Tools

Etsy - Entertainment

Bing Search API - Search

Reddit - Entertainment

Parse - Backend

Github - Tools

HNSearch API - Search

Google Drive - Storage

Stripe - Financial

Dropbox Sync API - Storage

IFTTT - Search

Pebble Watchface SDK - Entertainment

Spotify - Music

Google Mirror API - Tools

TradeKing - Financial

Tumblr - Blogging

Instagram - Social

YouTube - Entertainment

Coinbase - Financial

AngelList - Tools