Your blogger, greymatter, mt tags can go here. If you have your blog set to have very many entries on the front page, you will notice that the blog column will become longer than the other two. The height setting is changable within the style sheets.
Fill the columns at the right to your liking. The possibilities are endless. Also, if you require help you can use the support forums and/or the help files at 1greeneye.net.