Re: A study?
"[...] Office 365, [...]"
The "demon.co.uk" Office 365 mail service puts some emails in the "Junk" folder on IMAP.
It tends to accumulate emails generated by a form on my web site for users to submit names for faces on photographs. No attachments - but the subject line is usually the same as it indicates the photograph they are referencing. The content has a fixed format but the data content will differ in several named fields.