This is a must in Email Marketing.
For instance, do not start off in your Intro. Email telling your Subs how much you hate SEO ....and then 2 weeks later start Promoting a Product to those same Subs on back linking and getting ranked in Google
Bad move !!
Or if you talk to your Subs and emphasize the importance of a stable long term healthy lifestyle with no quick fixes. And then the following month you promote a Program that details how to lose 20 lbs in 10 days following a liquid diet
You really think none of them will call you out on this ??
Personally, I have Unsubscribed to Lists in the past in very similar cases.
So keep it congruent ,which really should not be hard at all if you are Trustworthy to begin with
- Robert Andrew