In this paper, we present a framework to analyze and summarize the temporal dynamics within personal blogs. Blog temporal dynamics are difficult to capture using a few class descriptors. Our approach comprises (1) a representation of blog dynamics using self-similarity matrices, (2) theme extraction using nonnegative self-similarity matrix factorization, and (3) a visualization representing blog theme evolution. Summaries based on large real-world blog datasets reveals interesting temporal characteristics for four blog types – personal blog, cooperative blog, power blog and spam blogs.