Blogs facilitate online debates and discussions for millions of people around the world. Identifying the most popular and prevailing topics discussed in the Blogosphere is a crucial task. This poster describes our novel approach to the quantification of the level of topic propagation in the Blogosphere. Our model uses graph-theoretic representations of the Blogosphere's link structures that allows it to deduce the `Percolation Threshold', which is then used in the quantification and definition of a global topic. The result of our experiments on a blog collection shows that our model is able to quantify the propagation of topics. Moreover, our model is successful in identifying specific topics that propagate throughout the Blogosphere and classifies them as `Global'.