Remember WordPerfect? This word processor dominated the world until Word wiped them out. How did that happen?
WordPerfect was the default word processor in every law firm, big company and organization in the land. If you had the DOS operating system, it was likely you were using WordPerfect. And, if the operating system in the office hadn't changed to Windows, it's likely you'd still be using it now.
What happened was that the change in operating system created a moment when people had to pick. They had to either switch to Word or wait for a new version of WordPerfect. In that moment, "do nothing" was not an option.
Do nothing is the choice of people who are afraid. Do nothing is what you do if too many people have to agree. Do nothing is what happens if one person with no upside has to accept downside responsibility for a change. What's in it for them to do anything? So they do nothing.
The key moment for an insurgent, then, is the time of "pick anything." That's why these are such good times for iPhone apps. That's why the beginning of an administration is a good time to lobby. When people have to pick, they have to confront some of the fear and organizational barriers that lead to the status quo.
It seems to me, then, that the best time for a marketer to grow is when clients have to pick something. Seeking these moments out is inexpensive and productive.
[Lately, this post has been paraphrased as, "Nothing is what happens when everyone has to agree." That has a nice ring to it.]