The technical difficulty over the last several days with posting comments has nothing to do with your IP address being blacklisted for malicious reasons. Trust me on this.
Even I found myself blocked from commenting and posting (although, being the sneaky little devil I am, I knew how to get around the issue).
It appears a blacklist used by one of the pieces of security software I utilize became rather generous in dealing out wicked reputations. For every IP address queried.
I should point out this particular software package enjoys widespread use on the web. Every site using it had the same problem.