Title: Please see http://ycombinator.com/ideas.html and feel free to add your own.<p>1. Spotify (for the music element)
2. Chrome
3. Twitter/BBC News
4. service-now.com
5. 37 signals
6. ??
7. ??
8. Match/Plentyoffish
9. Facebook
10. eBay
11. Google Docs/ Zoho
12. Adwords/Adsense
13. University of Phoenix
14. ?? 
15. ??
16. Bing
17. Paypal
18. ChromeOS
19. AWS/Rackspace
20. Thefind
21. Mint/Quickbooks
22. Google Docs/Zoho
23. ??
24. ??
25. Gumtree/Facebook
26. ??
27. ??
28. Gmail with filtering
29. Too many to list
30. ??
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