Blogs vs. Theme-Based Content Sites
Site Build It! (SBI!) owners build Theme-Based Content Sites. They build traffic right into their sites from DAY 1 by following the Content 
Traffic PREsell Monetize process. They build valuable sites that are searched-and-found by prospective new customers... with the number of visitors steadily climbing as their sites gain in relevance and reputation at the Search Engines.
Let's compare that with blogging...
Blogging is merely another way to build a Web site. Its content tends to be temporal or time-sensitive (ex., news-oriented or "the latest" or "the thought of the day"). And that is blogging's first major drawback.
Blogging is heavily covered by the media because they "get" the concept. They themselves create time-sensitive info every day. The great-untold story of blogging, however, is how 99+% of blogs lie dormant. Dead. And THAT failure rate is the second very big drawback.
As Chris Anderson, executive editor of WIRED magazine and one of the most prominent bloggers, said (in Blogging Heroes, a book published by Wiley in late 2007)...
