A successful blog would seem to be as interesting as the person(s) who are writing the blog; engaging content makes it more likely that readers will subscribe and return. What makes a successful blog seems to be the main thing that libraries should consider before starting one. Some of the questions a library should ask itself before starting a blog are:
Is the blog mainly to disseminate information, or is it meant to create a dialogue with its readership?
What kind of information is the library most interested in imparting?
Is the blog relevant for the population it is trying to reach?
What will be done to reach that population?
Is there staff available to not only maintain the blog but to write compelling content?
Is the library prepared to answer uncomfortable comments made by its subscribers?
In the online world of Facebook and Twitter length comments, I think that bloggers must be able to capture their audience in the first sentence of a blog post. Each following sentence should compel the reader to move onto the next until they have consumed all of the information that the blogger was trying to impart. This would also seem to suggest that blog posts should not be overly long for fear of losing those people who are used to reading online and may have shorter attention spans. I know that when I read blogs I tend to skim longer ones before committing to reading them in their entirety. A good blog is one that hooks me with the first couple of sentences thus ensuring the likelihood that I will read the entire thing as opposed to skimming it.