(FORTUNE Magazine) – 1. Internet billionaires should not own professional sports teams.

2. The Next Big Thing is never what you think it's going to be.

3. Banner ads don't work.

4. Mediocre old-economy managers make mediocre new-economy managers.

5. An IPO is not a branding event.

6. The best way to monetize your customers is to sell them a product or service for a healthy profit.

7. Giving stuff away is an easy way to make friends and a lousy way to make money.

8. Someday e-mail will not be free.

9. Physical stores are wonderful things.

10. An Internet business model that depends on a rising stock price is doomed.

11. "Aggregating eyeballs" is not, in and of itself, a business model.

12. If you have to ask "What's the business model?" you shouldn't own the stock.

13. If you have to ask "What's the business model?" there shouldn't be a stock.

14. Come to think of it, the world was a better place before the term "business model" came into vogue.

15. We should have listened to Warren Buffett after all.

16. You can't have a wireless revolution without cell phones that work.

17. Venture capitalists always make out.

18. As in every mania, the small investor is the one left holding the bag.

19. Your teenager will decide which technologies you use in the future.

20. Napster may win or lose in court, but copyright law will never be the same.

21. If you let it, the Internet can revitalize your corporate culture.

22. Youth is not the same as intelligence.

23. Wealth--even instant wealth--is not the same as intelligence.

24. "Cool" is not the same as "profitable."

25. A Website is not the same as a business.

26. The best streaming-video technology has existed for 50 years; it's called television.

27. Chat rooms are a fine place to pick up misinformation.

28. We are all living on Internet time.

29. If you let it, the Internet can decimate your corporate culture.

30. Salon.com will die long before Hustler.com.

31. The person to figure out e-cash will be a billionaire.

32. The low-hanging fruit has already been plucked.

33. You should have bought Qualcomm two years ago.

34. You should have sold Amazon six months ago.

35. You should never have bought Theglobe.com.

36. If you can't come up with a rational explanation for why a stock keeps going up, eventually it won't.

37. Burn rates are a more important metric than page views.

38. The experience of participating in a reverse auction to buy 13 pallets of laser-printer paper has been overhyped.

39. Amazon is not going to put Barnes & Noble out of business, much less Wal-Mart.

40. C. Everett Koop should never have come out of retirement.

41. William Shatner should never have come out of retirement.

42. Day trading is a sucker's game.

43. You're not really a millionaire until you've sold the stock (and paid the tax).

44. People who left good jobs for speculative options got what they deserved.

45. Let's face it: Nobody wants to buy shampoo over the Internet.

46. The Internet has made people care about privacy.

47. Breaking the connection between effort and reward is ultimately an unrewarding effort.

48. Creating Web companies has turned out to be much, much harder than anyone realized.

49. The Internet decade has seen the unscrupulous rewarded, the dimwitted suckered, and the ill-qualified enriched at a pace greater than at any other time in history. The Internet has been a gift to charlatans, hypemeisters, and merchants of vapor...

50. ...and despite all that, it still changes everything.