One of the more annoying things that I keep bumping in to in my "GTD it" thing is this: 
When mailing list providers require me to log in to unsubscribe from a mailing list.
If I am unsubscribing from a mailing list, it should be a one-click operation. Why? Because the alternative is me making a spam filter. If it's a choice between me losing focus unsubscribing from your newsletter or me hitting "Create a filter", it will be the latter.
Would you rather know that I've unsubscribed or would you prefer that I just have you automatically sent to Trash? That is the decision you need to make when deciding how to deliver e-mail.
And unless it's personalised, offer a damn RSS feed! E-mail is not a broadcast medium, RSS is. Give me the RSS and I can then subscribe and unsubscribe at will.
Oh? You can't track that as easily. Tough. In this age, my attention is all I've got, and if you fuck with that, you will have your e-mail marked as spam.
