I have been using Windows Live Writer everytime I post an article to my blogs,
in wordpress and blogspot and I love it very much.
Now, on every post i made i usually add split posts in wordpress, split posts is where
your article looks a summary style in your homepage, and there’s a link Read More » to read the full content of the post.

Windows Live Writer add it to the toolbar so that you can insert that easily
when your using a wordpress blog, but when you’re using blogspot,
WLW it can’t detect that your blog supports that feature.

Here’s a plugin for that, just Download Blogger Excerpt.dll and copy it to
C:Program FilesWindows LiveWriterPlugins (or “Program Files (x86)” if on x64 systems)

Now everytime you make an article to blogspot and want to add that read more or split posts feature like in wordpress, go to the line where you want to split the post and click on Insert > Blogger Excerpt…

Thats it! Thank you for reading and hope this helps to others using Windows Live Writer in Blogspot.
Source: Scottisafool