According to eMarkter.com:
"Currently, 96.6 million US Internet users read a blog at least once per month, representing 48.5% of the Internet population. By 2013, 128.2 million people, or 58% of all US users, will take part.
The numbers of bloggers is also rising. In 2009, 27.9 million US Internet users have a blog they update at least once per month, representing 14% of the Internet population. By 2013, 37.6 million will update their blogs at least monthly."
This is good news and bad news for bloggers. First, the rising number of blog readers is great news. This makes blogging a high impact activity. For companies and individuals looking to use blogs to extend their brand, more eyeballs are more potential customers. For entertainment bloggers who seek to build an audience and then drive advertising revenue, more potential viewers is great news.
The bad news is, that the number of blogs is growing. As this happens the market will become saturated and you will have to create stellar content to rise above the sea of mediocrity. Of course, this is an opportunity as well. In blogging, quality will win over quantity. Keep creating compelling, strong content that people love and your blog will continue to attract and retain followers.