The statistic or something similar to it has dominated the sales pitches and marketing materials of search engine optimization companies for a very long time. I just saw a mention of it in an article from 2005 and it’s been reiterated again and again ever since. Nearly every study seems to come to the same conclusion. Nearly every study is wrong, at least from a business perspective.
For those with a business that has an active blog, you may say that this seems light. It is. It seems that there’s a huge gap between those who are adding content to their site and those who don’t so we’re going with a strong minimum. If you’re adding two pieces of content per month, you have the ability to make a difference.