This is to share on how to prevent the problem of ending up in these email providers Spam folders.  Using CiviCRM contact mail link and Civimail, I have continually ended up in these forlders.

I will touch on Yahoo first then come back later to Gmaill and Hotmail

Yahoo
1. Add SPF to your TXT Zone file for DNS.  To me this meant going to Godaddy and following their very easy to use instructions.  I also use Networksolutions for another Domain and they where NO help so I need to figure out what to do with them.

FIRST go here to test http://senderid.espcoalition.org/ then you will see, most likely you are missing some settings.

2. Then this site will help you find you SPF settings http://old.openspf.org/wizard.html

3. Once done try the test site again and you will see better results.  Now you will also see your email go into the Yahoo Inbox.

Yahoo also has a form you can get to get you off the list http://help.yahoo.com/l/us/yahoo/mail/postmaster/forms_index.html

Let them know what you want and you will get a form like http://forum.civicrm.org/index.php/topic,1484.msg6480.html#msg6480

You will see there the form they sent me and the good advice given.
 GMAIL

1. Following the above is a good start.  This helped overall with my email to Google. 
Coming soon more on this.

Hotmail

Coming soon more on this.
- http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/

Others

http://spf.pobox.com
http://spam.abuse.net/userhelp/howtocomplain.shtml
http://www.openspf.org/

Later

1. Make sure all your mail servers accept mail from: delivery notifications (NDR)
2. Make sure your DNS is properly set up and that you are complying with the RFC rules regarding service configuration;
3. Deploy Domain Keys and SPF for outgoing messages;
4. Make sure that your mail servers has a reverse DNS entry. Some servers will reject mail without a valid reverse entry specified