What we learned watching AOL stumble

[Commentary] AOL's trajectory is a bracing reminder for today's tech sensations that their success is vulnerable, especially at its peak. It is a cautionary tale of what not to do when you have the world by its tail. Here are a few AOL lessons:

• The hockey stick growth mystique: AOL prospered by drawing millions of people to its service, but that growth, which peaked at nearly 30 million dial-up customers, was challenged by the uptick in broadband adoption.
• The allure of the "transformational" purchase: Make acquisitions, but not ones so big and culturally at odds with the firm's central mission that the combination destroys the resulting company.
• Feeling invulnerable: AOL Time Warner was immediately besieged by problems of its own making, but what took it down ultimately was the dot-com bust. The firm had to write off billions and its stock lost significant value.