Mapping the connections between student blogs

I was wondering if anybody could point me in the right direction of how to map connections between student blogs for a research project.

I want to track comments that happen between student blogs in my class and see some sort of 3D representation over time, including number of connections in a day, week or month, how many times between certain bloggers etc.. I'm not sure how easy it would be to automate this process, but I am willing to manually input the data (with my students help) and need to find some type of software or app to make this happen. If it looks like gapminder all the better.

I want to track the connections between the blogs and then use another set of criteria to look at the content of the blogs themselves.

Any pointers would be much appreciated.

Cheers,
Andy