AOL's new Postmaster Blog reveals that the new version of the AOL webmail interface now blocks links by default.

Now, when sending to AOL.com/AIM.com users, your message will have a banner across the top that says “Enable Links (for this message) | (always for this sender),” somewhat similar to what Outlook does. Recipients can choose to enable links for that one message you've sent, or they can permanently enable links for messages you send them by clicking on the “always for this sender” link.

On another note: If you happen to poke around the AOL Postmaster Blog, you'll find this post talking about how AOL wants you to minimize your attempts to deliver mail to invalid recipients. One of the “are you a spammer?” measures that ISPs use against you, is what percentage of your attempted mail is undeliverable. If your list is chock full of bounces, it's a sign of bad list practices. You look like you've bought a list, been sitting on a list for many years, or otherwise came up with a group of email addresses that are far out of date and invalid. Good senders don't have this problem; they mail regularly, only to people who really signed up to receive mail from them. Good senders also process bounces properly; invalidating, and ceasing sending to, addresses that bounce back and aren't deliverable.

AOL doesn't lay out an exact “bounce threshold” -- they basically say “don't be on the bad end of the sending spectrum.” It highlights that AOL isn't willing to provide a bar to allow all senders to slide “just under” as needed; they're concerned about questionable senders gaming the system. Instead, they're working based on a process wherein they identify the spectrum of senders and their associated statistics. They then stack rank senders, and take those on the lower end of the ranking (the poorest senders) and those are the ones they're likely to take action against.

Working this way suggests to me that their hope is to significantly raise the quality of mail their users receive over time.

I've heard the occasional bit of grumbling here and there from various senders and other ESPs about how it's not fair and AOL should simply publish an exact threshold and make it clear what the rule is. I don't blame AOL for addressing it the way they are. I know that ISPs are deluged with mail from “edge case” senders trying to do just enough to get by under the radar and get their mail delivered, without a true commitment to permission. I certainly can't blame an ISP for changing things up in a way that hopes (I think) to trip up iffy senders.

Besides, if you're not an iffy sender, what do you have to worry about?