Popularity of the Paleo Diet on internet has grown 400%+ in the last 3 years.
Take a look at this search you can do on Google Trends.
When I originally wrote this post in 2010, the Paleo Diet was becoming quite popular. It went on to be 10x MORE popular after that in 2013. Interestingly however, its popularity has been on the downward trend since.
The fundamentals of the diet, obviously, have not changed and it is still be the basis of any healthy modern diet.