AOL Is Looking for Input From ISPs and ESPs

Just read this on Laura's excellent Word to the Wise blog and thought I'd help spread the word:

AOL is looking for input from ISPs and ESPs to better understand how you handle data sent to you by AOL.

In regards to bounces - users unknown, specifically - could you please explain the following:

• ESPs: When do you take action on clients because of bounces? What is your threshold for acceptable, and not? Do you have an escalating level of punishment for people who break your thresholds?
• ISPs: What is your threshold for “acceptable” in regards to inbound mail streams and “users unknown”? What do you do when that threshold is breached?

Here's where you should submit your responses to. Do NOT answer them here because Laura won't read them here.