I got 6-8 notices from a web site/organization saying I had unsubscribed. I had not done so and I didn't want to. It was quick and easy to join back on again but it got old. These guys are very sophisticated computer users. I wrote to them and asked for information about who was unsubscribing me.
They got back with the answer. "Bots" were doing it. Naturally, I had not considered that possibility. Look it up. Watch YouTube videos. I found that bots, or web bots or web robots are actually scripts that some machine or other can operate. The usual term is "execute", not as in killing someone but as in carrying out a task. If you have ever tried to alphabetize a group of titles and compared the time it takes with having a spreadsheet or other computer application to the job, you have experienced the truth that computers can do it much faster.
Much like a mailing group can enable a user to paste many email address in a message in a flash, much like a "macro" in Excel or other software can carrying out a series of steps in an instant, a bot can perform repetitive and complex tasks tirelessly and very quickly. From what I learned, I gather that once in a while, some sort of bot goes over what I post in my blog. I guess where a message says "Unsubscribe here" with a link, the bot jumps to the task. I assume it unsubcribes me efficiently and quickly.
I am glad I learned to think of bots once in a while. I have heard that machines, artificial intelligence and other sources of both power and frustration are advancing into my life and I think that is true.