On Mon, Sep 12, 2022 at 4:16 PM Paul Kincaid-Smith <p...@emailgrades.com> wrote:
> > We have a reasonably large sample of messages sent from Gmail, Yahoo and > Outlook and can assess how much was "spam foldered" by each of those > services. We are in the same ballpark as John Levine, who estimated that > "about 30% of the mail I get from Gmail is spam." > > EmailGrades collects metrics about senders and receivers, primarily to > measure inbox placement and recipient engagement for commercial ESPs vs a > cohort of their peers, but we also have insights regarding messages sent by > mailbox providers like Gmail, Yahoo and Outlook. For the month of August > 2022, millions of messages received from Gmail, Yahoo and Outlook's > email infrastructure by hundreds of thousands of panel mailboxes reveals > the following spam foldering rates: > > Received at Gmail | Received at Yahoo | Received at > Outlook > Sent from Gmail 16% 38% 49% > Sent from Outlook 47% 78% 47% > Sent from Yahoo 5% 3% 9% > > The way to read this table is, "Of the messages received by our Yahoo > panel mailboxes, 38% of those sent by Gmail were routed to Yahoo's spam > folder" and "Of the messages received by our Outlook panel mailboxes, 9% of > those sent by Yahoo were routed to Outlook's junk mail folder" and "Of the > messages received by our Gmail panel mailboxes, 47% of those sent by > Outlook were routed to Gmail's spam folder." > Does this indicate actual spam or just marked spam by the mailbox provider? Does this indicate authenticated by the sender provider, or less? This gets even more complicated when you talk dkim replay. Anyways, this also may indicate something else we know, which is that spammers know that spamming another gmail account is a great way for us to find them, so they tend to use Gmail to spam non-Gmail. These numbers are also worse than when I worked on Gmail years ago, but it's always possible things got worse. > All other things being equal, Outlook filters messages from Gmail most > aggressively. Yahoo filters messages from Outlook most aggressively. > Outlook filters messages from Yahoo most aggressively. > > Outlook's spam percentages are higher than Gmail's but that may be because > Outlook chooses to block less outbound mail and instead flags > questionable outbound messages, sending them via a pool of IPs that ought > to receive additional filtering scrutiny. > I expect any reputation based anti-spam system should be able to tell whether an MSP does this. Google definitely had separate sending pools for various things in the past, and does expect that receivers would eventually learn and apply differential filtering based on that. No idea what the current system does. Brandon
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