"As a business owner, I'm continuously having to do things so I don't end up in spam. Less images, specific wording and the list goes on."
We[1] run our own mail and DNS servers and, as you might imagine, have never sent a single HTML email or any email with any kind of "element" in it, etc.
Just plain, ASCII text.
We've got a 15 year clean IP, perfect score on the "mail config checkers" and almost every single email we send is in response to an email from that sender.
And yet ... often enough to make me anxious, we get marked as spam.
We have the same issue. Online surveys being sent as invites to 100s of 1000s of people per day and although we are good at spotting SPAMMERs setting up free accounts, obviously people will always receive an invite they might consider SPAM and we get derated. Persnally, we find Yahoo is the worst for blocking.
It would be good to have a central registry of mail forwarders so that SPAM is not detected against registered IPs and then issues can be followed up directly with anyone who abuses the system. Do you really want to greylist Amazon SES because one of its users sends out spam?
Sending text-only is probably a weak spam signal as far as Gmail is concerned; for the majority of mail to the majority of recipients (though yours may be exceptions), HTML email - even if very basic - offers better layout/design options and better readability.
On top of that, of very old-school users on Mutt or Pine who prefer text over HTML, I'd think a significant portion of them don't have their mail pass through Gmail's filters.
We[1] run our own mail and DNS servers and, as you might imagine, have never sent a single HTML email or any email with any kind of "element" in it, etc.
Just plain, ASCII text.
We've got a 15 year clean IP, perfect score on the "mail config checkers" and almost every single email we send is in response to an email from that sender.
And yet ... often enough to make me anxious, we get marked as spam.
[1] rsync.net