I'm with you, windowless envelopes are the way to go.Windowed envelopes have the connotation of being a bill, credit card offer, or spam mail and we do not want our letters to scream "SPAM!!"

@Brandon Turner, @Joshua DorkinNow that the subject of the topic is gone, these have no use and are more or less spam.

I've found out that they are very sensitive when it comes to flagging(deleting) posts that look like spam.  

It may have ended up in your Spam folder?

However, be careful with search engines which may see your strategy as keyword spam or spammy links.

I find it silly that someone comes to an open forum, free to the world, posts something great, then thinks it is annoying that he gets 10 minutes of messages that are spam. 

If not, ask him to stop, or just forward his emails to spam.  

They at least don't spam you with calls 3 times a day.Has anyone else had a similar experience? 

I would like to bigger pockets may consider this spamming. 

They ignore protocol, they spam, or they do one of a dozen other things that don't fly here (or on most other credible forums).