Many email providers (may or may not be the same as your ISP) will take it upon themselves to block/filter certain emails to you (not all emails, only some emails), without asking if you want them to be blocked. The excuse use is that they are protecting you from Spam, junk mail, porn, etc. Good intentions or not, many of these email “protectors” or filters are often programmed in a very imperfect and prejudicial way. They may block anything with certain words in the “from” or “subject” line, or in the text of the email. They may block a website that has been reported for Spamming even if they did not send Spam (happens more often than you might think). They may block a website because it deals with what they consider to be a “dangerous” or “adult” subject like guns or firearms. They may block some emails and not others, and unless someone finds another way to contact you and tell you their emails to you are being blocked, you may have no way of knowing what emails you are NOT getting. But the most important thing to remember is they block emails THEY want to block using an imperfect system, not by your choice, and it is not under your control. These email providers often don’t let you choose to place certain emails or websites on an “allowed” list. Many don’t give you that choice (or they don’t make it clear that you can do this). How they get away with this is hard to say, since it is the email equivalent of your local post master choosing what envelopes and packages you will and will not get delivered to your home or office, but still they do get away with it. Below is a partial list of email providers who have demonstrated that they will block email without your permission and may not give it’s customers control over what to block and what not to block or they may not give clear instructions on how you can gain control over your own email inbox. You may not want to use these email providers if you want to have complete control over what email you do and do not get. Adelphia.net AOL.com CenturyTel.net Clearwire.net Earthlink.net (if using the Earthlink Spaminator or SpamBlocker) Optonline.net (if using the SenderScore.net system) Verizon.net Yahoo.com And the list keeps growing.