A number of people, both at ESPs and on the mailops mailing list, are reporting problems at Hotmail. The most common reports are senders getting
Site hotmail.com (65.55.92.152) said in
response to MAIL FROM (452 Out of memory)
during the SMTP session.
There isn’t much senders can do about this. Hotmail is going to have to fix their resource issue. This may be limited to certain mail clusters, so watching the IP addresses reporting this error and avoiding them may help.
ISPs are continually developing tools for their users. Some of the newer tools are automatic filters that help users organize the volumes of mail they’re getting. Gmail released Priority Inbox over a year ago. Hotmail announced new filters as part of Wave 5 back in October.
All of these announcements cause much consternation in the email marketing industry. Just today there was a long discussion on the Only Influencers list about the new Hotmail filtering. There was even some discussion about why the ISPs were doing this.
I think it’s pretty simple why they’re creating new tools: users are asking for them. The core of these new filters is ISPs reacting to consumer demand. They wouldn’t put the energy into development if their users didn’t want it. And many users do and will use priority inbox or the new Hotmail filtering.
Some people are concerned that marketing email will be less effective if mail is not in the inbox.
Hotmail has recently stopped using Sender ID for email authentication and switched to authenticating with SPF. The protocol differences between SenderID and SPF were subtle and most senders who were getting a pass at Hotmail were already publishing SPF records.
From an email in my inbox from September:
There are a number of sites online that provide public information about reputation of an IP address or domain name.
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