How do I stop Following that blog? It's not listed, in "Manage Blogs I'm Following", and I never Followed it!
When you check the "Manage Blogs I'm Following" wizard, you get a list of the blogs that you Follow, with the Settings link for each.
Oddly enough, these mysterious blogs - that you can't remember Following - won't be listed, under the observed title, on the "Manage" wizard display.
Some blogs, for one reason or another, will redirect their feeds to another blog or website.
Other blogs may simply no longer publish a feed. In some cases, this will leave people seeing completely unrecognised - or unwanted - content, in their Reading List.
Fortunately, it's not complicated to find these mystery blogs, and remove them from your Reading List.
Any unknown content, listed in the aggregated reading list, will also be listed in an individual entry underneath "All blogs". Just go down the list, overlooking the titles, one blog at a time, and you'll find the unwanted content.
Once you identify the titles of the blogs that contain the unwanted content, go to the "Manage Blogs I'm Following" wizard, find the problem blogs by title, and remove the unknown blogs.
Then contact the blog owners, and tell them the mistake that they made. Alternately, report the gullible blog owners, so Blogger Support can inform the owners.