The blogosphere is often cast aside in favor of social networks and microblogging sites, but maybe marketers should rethink their social outreach strategies. Invoke's recent Life and Social Networking survey, relayed by eMarketer, shows that more than one-third of consumers (36 percent) look to brands' blogs as trustworthy sources of information, compared to roughly one-quarter (26 percent) who thought corporate tweets were reliable. This means blogs are the second-most trusted sources of industry info offered by businesses, closely following Facebook.

In light of this news, it may not be surprising that many marketers are planning to increase their blog efforts in coming years, and those without blogs may want to get started. An eMarketer report released today indicates that 34 percent of U.S. companies are using blogs for marketing purposes this year, but usage will jump to a predicted 43 percent by 2012.

"Companies are finding that blogs fill a specific niche that other forms of social media do not," said eMarketer senior analyst Paul Verna. Verna says marketers generally perceive blogs to boost brand awareness, generate leads and drive traffic to websites more effectively than other social sites do.

This may be true. Running a Google News search for "Google blog" reveals that more than 5,800 current news stories refer – and frequently link – to official blog posts from the company. Skype and fring also found that blogs can prove invaluable linkbait and boost brand awareness when the two engaged in a widely covered war of words earlier this year via their blogs.

In spite of these big brand success stories, officials at eMarketer predict growth in brand blogging will be driven primarily by smaller firms, a prediction that correlates with a recent study from the University of Massachusetts Dartmouth Center for Marketing Research. The survey shows that adoption of blogs was much more prevalent among fast-growing, smaller companies than it was for Fortune 500s.

Nonetheless, marketers for companies of all sizes may want to consider creating interactive blogs for their brands. The Invoke survey found that the quality of comments impacted 62 percent of consumers' perceptions of a business blog, and 60 percent said the responsiveness of sponsors or authors played into whether or not they trusted a blog.