It’s annoying when you have your comments inbox filled with useless senseless comments with nothing but links to annoying sites you have no interest at visiting at all. If you don’t have a good spam blocker plugin installed in your blog you can take forever deleting these spam comments to come back the next hour or next day with your inbox filled with spam again.
If you are using WordPress as your blogging platform, then you can simply install the Akismet plugin and it will do most of the job for you. It is mostly 99% accurate although there are a few comments that can pass through it’s filtering system. When this happens and the same commenter keeps spamming you like 100 times a day you will have to manually block them from commenting in your blog forever.
You can do this by getting their IP address from the comment they posted on your blog. Go to the settings tab on your dashboard and input their IP address on the blocked host tab. It will take a day or two to get that IP blocker do its job so until then be patient with deleting comments from this bozo for a bit more.
If your problem is someone harassing you on the email. What you can do is scare them by giving them bits of information about their computer system and location. You can do this with this Track IP Addresses which will give you a lot of information about their internet service provider, the internet browser they are using, the operating system they are using with their PC and plugins they have installed in their computer. Send the information you know about them via email and tell them to bug off or else.