The loads of examples all leads to show one thing - the point when something (or anything) can become 'big'. That is what is the tipping point. Part of the reason is the 'cool' factor people associate with.
In between, Malcolm also shows some other interesting theory like the 'Broken Window' - which describes how one broken window can affect the whole road of houses to eventually have the same. I would like to put it as another term - maybe 'Bright Window'. Like when one shop is beautifully renovated, the rest in the road will eventually follow suit, turning some roads far beyond recognition (for the better). He also talks on the 21 days ritual and turning that into habit.
A little hard to read as there seems like no ends of examples at times, however, this book is a must read for marketers who has big visions, and for others who would like to know how the world works. Though the author doesn't particularly conclude what really works, his insights to his vast knowledge is still well worth the input. My conclusion falls back that to have a tipping point, you need to make it 'cool' :)