If I’d signed up to your list knowing that was what you were sending then it would be OK – as long as it contained other useful stuff.
If it was just an advert I’d delete it – unregister from your list – and think less of your site.
So I’d suggest keeping it to your newsletters and perhaps as a teaser line with a link to a webpage (so you can count responses).
Maybe even add a poll to your site asking how the recipients felt about it.
You’ll soon get a feel for your members opinions.
:popcorn: