Following is an excellent example of what the web is good for - connecting people. Unfortunately, some people doing the connecting don't have honourable intent. Blogger Following, like everything else on the web, can be subverted by the hackers, porn merchants, and spammers. But not if we don't let them do so.
Fortunately, Following is going to require more effort by the spammers, and it will take longer to produce results that they will appreciate. And we can prevent their effort from producing their desired results. All that we have to do is examine our Followers list, and Block any undesirables.
If you are properly logged in to Following within your blog, you'll see your icon at the top of your Followers window.
If you're not logged in, you'll see a link to "Sign in". Click on the link, and sign in.
Click on any Followers icon, to open the profile display.
Seeing your icon in the Followers window, you have only to click on a Followers individual icon, and the profile for that Follower will open in the Follower window. Right at the top of the Followers profile, next to their icon, you'll see a link to "Block this user".
Alternately, start from your profile dashboard. Any popular blog will show a count of the Followers for that blog - and the count will contain a link. Clicking on the link takes you to the Followers list for the blog. Clicking on the icon for any Follower gives you the profile for that Follower. If you are an administrator for that blog, you should see a link to "Block this user".
"Block this user" blocks the icon from the facepile only.
Remember, when you "Block this user", you simply remove the icon and link from your Followers community. Anybody who wishes to Follow your blog (ie subscribe to the blog feed) can do so with impunity.
A blog feed, available to anybody, is available to everybody. And there's no way to disable the links attached to the icons either - if you can see them, your readers can link to them.
Note two additional details about blocking Followers.
Watch your Followers community regularly, and eventually you'll get an instinct for which Followers are genuine, and which ones are Following you simply to get a backlink to their splog.
Keeping your Followers and Followed blogs clean is a good idea.
Keep your Followers list clean, and those who Follow you will appreciate it. And likewise, those who you Follow will appreciate it.
And besides keeping a careful eye on your Followers, it's a good idea to remove any blogs which you don't care to Follow, or that may change content.
Using the "Manage" button at the bottom of the Reading List, you can change any Following relationship between public and private, or stop Following, altogether. Keeping your Reading List clean (of blogs that you don't really care about) will help you enjoy the blogs that you Follow (and that you do care about).