The latest release of the DNN Blog module does not place the blog title in the page title tag. To remedy this, IT Crossing staff have created a quick workaround to this issue.
To implement this solution, simply download and install the module below and add the module any page containing the DNN Blog module. The attached module will place the title of the blog entry in the page title tag. Source is included and there's only 3 files, so it should be easy to understand and modify.
IT Crossing DNN Blog Title Fix