Blogs are increasing in popularity as an easy to promote website. Blogs
tend to have better search engine visibility and rankings and they have
many advantages over conventional websites.
Each blog post is
worth a few backlinks straight off the bat. This is because each time
you post your blog software pings services like technorati which then
link to your post. The more you post the more backlinks you get and the
greater your chances of higher page rank.
Blogs also seem to
have more "pages" of content than static websites. Consider in how many
ways a single post appears. It can be accessed through your frontpage,
archives, category overview, tag overview or as a single post. In
almost every case it appears alongside different posts that together
make the whole page unique. This is why blogs have more pages and SEs
like websites with lots of pages.
By its very nature a blog is
designed to be updated regularly. SEs love websites that have fresh
content and so they will rank a blog with regularly updated content
better than a static site that is only occassionaly updated.
Blogs are also easier to promote because they provided rss feeds that your users can subscribe to.
One
of the most important factors behind SEO is the need to have your
content at the very start of your web page. Since a lot of blogs favour
the right hand sidebar, they usually have most of their content at the
beginning of the source code. This makes them more search engine
friendly.
For all these reasons blogs are easier to promote.