RememberTheMilk: is the popular to-do list that's everywhere you are: from your phone, to the web, to your Google apps, and more. Used by millions worldwide.
Readitfor.me: Readitfor.me is one of the most affordable ways to transform your future. We'll give you beautiful, engaging visual summaries of the world's best ideas.
Summary.com: Executive book summaries, reviews & webinars of the best business books.
Heyo: helps you easily create Facebook contests, sweepstakes & mobile-optimized landing pages to help you get more fans, leads and sales.
Commun.it: Grow followers & manage multiple profiles with Commun.it
Endomondo: is a sports community based on free real-time GPS tracking of running, cycling, etc. Bring your mobile on the track and get a complete training log!
Marketing Land: Provides internet marketing news and analysis, along with columns covering practical tips and strategies to succeed with
MarketingProfs: One source for online marketing resources, marketing strategies, marketing articles, online seminars, case studies, conferences and events for Marketing
Dropbox: Dropbox is a free service that lets you bring your photos, docs, and videos anywhere and share them easily. Never email yourself a file again!