Mark Penn Responds:
People have raised questions about the calculations on the numbers of bloggers for hire. First, I was surprised at how few studies there are on this and I believe there definitely should be more. So perhaps in the future I will do some original research, but for this piece we took the best we could find and referenced every number so people would know where they came from.
There is no question that the blogosphere, fast-growing as it is, has yet to nail down one way to measure itself or gauge its activity. But the most comprehensive sources we could find, conducted by reputable professionals, say there are over 22 million bloggers out there; and that 2% of bloggers are making their living blogging. Do the math, and you get roughly 450,000. It’s a fast-growing group and we ignore their needs, and influence, at our peril.
As far as the $75,000, the Technorati report says that of those bloggers who had 100,000 or more unique visitors, the average income is $75,000. True, it’s not the median, but it is the average. We can quibble about how easy it is to make this kind of money — but the point is, the huge potential is there.
Read more details on the sources and calculations