Taking the domains of all the posts and sorting by posting frequency according to the 24 hour dataset, the top 20 domains are as follows:
It is interesting to see how the simple time series provides some pretty clear insights. Here is a graph showing the posting frequency for the total data set as well as those for msn.com, blogspot.com and findallarticles.com. Where as msn.com (blue) and blogspot.com (green) follow the global trend, findallarticles.com (red) shows a very steady flat trend. Not surprisingly, this is a spam blog. Note also how there are a couple of outage points for the spam blog which are reflected in the global time series as dips in the data.
I'm not going to guess why that is just now, but it is interesting to say the least. In fact, looking at this graph suggests that another interesting graphic is going to be the timeseries of posts with msn's removed to see how much it accounts for the overall trend.