Blogs have become entrenched in mainstream life, according to the 2008 "State of the Blogosphere" report that found bloggers are adding new posts at a staggering rate - more than 37,000 per hour - to their increasingly profitable blogs. That growth, the report said, has attracted the attention of companies who are turning to such blog sites to promote their brands.

The blogging report, slated to be released in five parts this week, was compiled by blog search engine maker Technorati, which has taken the pulse of the blogosphere annually since 2004. This year, the company added a new wrinkle, surveying more than 1,000 registered Technorati bloggers from more than 60 countries to delve into their lives as bloggers.

Technorati is tracking 133 million blogs, 7.4 million of which added a new post within the last 120 days. On average, the search engine tracks 900,000 new blog posts every 24 hours, 10.4 new posts per second, according to the report.

The majority of the bloggers surveyed have advertising on their blogs, with a mean annual revenue of US$6,000. The report said that bloggers who pull in 100,000 more unique visitors per month generated an average annual revenue of US$75,000. The bloggers surveyed have been posting for an average of three years. Two-thirds or them are male and 70 percent have university degrees.

Four out of five bloggers are personal bloggers who write about topics of personal interest, the report said. About half of bloggers are professional bloggers - defined in the report as those who blog about their industry or profession in an unofficial capacity. About 12 percent of bloggers blog in an official capacity for their company.

The majority of corporate and professional bloggers reported that they have seen a positive impact as a result of their blog. Half said they are better known in their industry, and one in four have used their blog to bolster their resume, Technorati noted. Less than one in 10 has seen a negative impact from blogging, the report said.

While women bloggers are more likely than men to be personal bloggers, they are more sophisticated about advertising, the report noted and are twice as likely as men to sell through an ad network and more likely to have affiliate links. They are also more likely than male bloggers to link to other blogs, get listed on a blog directory and produce content for other blogs.

The report found that four out of five bloggers had posted a brand or product review, with 37% of them posting frequently. One-third of the bloggers reported that they have been approached by corporations to be brand advocates.