Probably someone scanning for vulnerabilities. Less likely, your blog I being used as a communication channel - either between human parties or to control somet

Probably someone scanning for vulnerabilities. Less likely, your blog I being used as a communication channel - either between human parties or to control something. I'm not sure how you'd find out. I'd strongly suggest installing a recaptcha plugin. At one time I was getting a lot of spam comments and this solved it for me.