You can use guest bloggers. You can also use reshared online content and expand your blog and provide more to read for your community of readers. There is excellent material on Google Knol.
Knol has the provision for resharing of knols on blogs and websites. There are many knols that specified creative commons license and all these knols can be reshared by interested bloggers and web masters.
I am developing a knol collection for facilitating such resharing.
Knols with Resharing Option - A Knol Collection
Visit the knol collection and click on the search link provided to see very popular knols with 10,000 page views and more available for sharing on your blogs. Share them on your blogs specifying the license and increase content on your blog.