I'm sure you've received messages from mailing lists and wanted to unsubscribe. Perhaps you don't remember subscribing in first place, or maybe you've just grown tired of subject. For whatever reason, you just want to get off list, and you want off fast.
On virtually every list, it is common practice to put unsubscribe instructions at bottom of every message (Yahoo groups, also called egroups, is an exception in that sometimes there are no unsubscribe instructions at all). You simply do what is described and you will be removed from list.
In most cases, a simple blank email to an email address or a clicked link is all you need to do. Sometimes you need to include word "remove" or "unsubscribe" in subject or body of message. It just depends upon conventions of list.
Now, this article only applies to mailing lists to which you have subscribed (opt-in). Before you click on any link or send an email off to parts unknown that message is not spam. Never reply or click on any links in spam - just delete message unread.
Don't get mad about receiving mailings from various lists. Most of these now require double-opt-in, which pretty much means you have to want to be subscribed. This is very safe for list owner because not only do list members subscribe to list, but they must also do something else (usually return a blank email) to verify that they indeed do want to subscribe.
It's generally not a good idea to try and reply asking to be removed from list. Most lists have specific unsubscribe functions and simply writing an email saying "please remove me" will not work. Quite often, in fact, a reply will instead be sent to ALL members of list, which simply makes you look foolish.
Also, list owner is using one of list services because it automates everything. Think of effort that he or she would have to do through of all requests were handled manually. Thus, it is in everyone's best interest to spend a couple of minutes to learn how to unsubscribe so it is done properly.