My digital library students have had a conversation this semester about whether blogs are scholarly. When I discussed this topic with one of our PhD students, he rephrased the question and used the words "authority" and "trust". Is a blog (or blogger) recognized as being an authority? Can a blog be trusted? To him, the answer is provided by the community. For example, it is the community of people that are interested in digitization who decide if this blog/blogger can be seen as being an authority and it is the community that decides whether it can be trusted.
Authority -- Who is an authority on hip-hop music? Those people who are part of the hip-hop music community are the authority. They are the ones that will look at a new hip-hop music video, web site or artist and decide if it related to the community. They will decide if that new artist really is a hip-hop music artist or a fraud. Since I'm not a member of that community, I am not an authority.
We often look at blogs, web sites, etc. and pass judgment about them as outsiders, not as members of their specific communities. While there may be aspects of a blog, for example, that we can judge, as an outsider we cannot judge the blogs authority. We need to turn to members of the community in order to discern that. We can look at inbound links (via a search engine) or at the authority as judged by Technorati, or talk to other members of the community. If members of the community see that site as being important, then it is.
Authority does not mean that others don't disagree with the information or that it doesn't carry can authoritative voice in other circles. It means that within that community the site/blog/? is considered an authority.
Trust -- The community also judges whether the blog/site can be trusted. Notice that trust is different than authority. Yes, these qualities can and do function independently of each other. What we want are blogs and web site that are seen by their communities as being authoritative and trustworthy. We want to know that we can rely on the information.
While you may not be a blogger, you need to be aware that whatever you do online is being judged by your community - those people who have the same subject area expertise, same point of view, etc. Are your efforts being seen as authoritative? Can people trust your efforts? If not, what do you need to change?