Why are OOO autoreplies ever marked as junk?

Question

I've noticed that OOO autoreplies get put in my junk folder not-infrequently. Why would this ever happen? I would think that junk mail filtering systems would have a rule that mail is never junk if it is from someone who I just sent a message to, and especially if the subject line is similar to that of my recent message.Why does this ever happen? In case it matters, my mail is hosted by gmail, and I access it via Mail on my Mac. I don't know whether gmail or Mac Mail is marking this stuff as spam, but both companies should know better!

temikus · Accepted Answer

Because it&rsquo;s sometimes hard to discern from Backscatter (malicious bounce messages).See: https://en.m.wikipedia.org/wiki/Backscatter_(email)

kl343 · Answer

If the sender is using Exchange Online, this might explain why OOO replies would be marked as spam more frequently:
https://github.com/MicrosoftDocs/OfficeDocs-Support/blob/pub...
"By design, Exchange Online Protection uses the high risk delivery pool (HRDP) to send OOF replies, because OOF replies are lower-priority messages."

comex · Answer

Perhaps people mark OOO autoreplies as spam after receiving them in reply to their mailing list posts or other mass emails.

fogihujy · Answer

My theory is that OOO's are (in general) short, and short messages have a tendency to end up in spam folders. The fact that people often don't use the spam buttom as a delete button probably doesn't help.Also, Gmail is a common source of spam, and they often end up in RBL's.

kiwijamo · Answer

Are these internal (i.e. from another Gmail user) or from another external system? I've never seen an internal (i.e. OOO from a colleague in the same organisation) marked as spam. I assume some email systems will treat their own OOO emails differently--and in fact I am pretty sure this is the case for Exchange for example. But I can see how it could happen for OOO emails from another system which would be handled simply as any other email.My money would be on Gmail marking the email as spam. I don't recall Mac Mail doing any special spam filtering.

hunglee2 · Answer

Very good point.Also wonder what the reputational risk is of setting OOO - auto emails that never get opened or replied to, are often labelled as spam - and left there. Preservation of my own email reputation is the reason why I never set OOO - would recommend others do the same

actually_a_dog · Answer

I suspect it has something to do with the fact that they're all written in a pretty similar way, and, over time, you'll tend to get a good number of them. Large numbers of similar sounding messages seems like a pretty good spam signal to me.

tomjen3 · Answer

Because they are junk, in the wast amount of cases.At least I consider them as such.

Why are OOO autoreplies ever marked as junk?

Because it’s sometimes hard to discern from Backscatter (malicious bounce messages).
See: https://en.m.wikipedia.org/wiki/Backscatter_(email)

Perhaps people mark OOO autoreplies as spam after receiving them in reply to their mailing list posts or other mass emails.

My theory is that OOO's are (in general) short, and short messages have a tendency to end up in spam folders. The fact that people often don't use the spam buttom as a delete button probably doesn't help.
Also, Gmail is a common source of spam, and they often end up in RBL's.

Very good point.
Also wonder what the reputational risk is of setting OOO - auto emails that never get opened or replied to, are often labelled as spam - and left there. Preservation of my own email reputation is the reason why I never set OOO - would recommend others do the same

I suspect it has something to do with the fact that they're all written in a pretty similar way, and, over time, you'll tend to get a good number of them. Large numbers of similar sounding messages seems like a pretty good spam signal to me.

Because they are junk, in the wast amount of cases.
At least I consider them as such.