For me, the typical flow is to go to blog and click on the logo at the top.
For the optimum marketing outcome, the top logo links to your main website.
In this case, the top logo links back to the blog. This site possibly lost the marketing opportunity because now I have to go to the trouble of clicking in the URL and changing it to www from blog. Might not sound like much but I think some people are willing to spend a few seconds having a look at something if it is incredibly easy to do so, but can't be bothered to make it happen if it requires anything more than a click.