First Contact

As the name suggests, a first contact message is the first message that you have ever received from a given sender. It may be that the sender has acquired your email address from your web site, your business card, or a mutual friend, but in any case the message is not a reply to a message that you have sent, or in response to a news letter that you have subscribed to - so you never know when you are going to get one, as such it is the least likely type of lost message to be discovered and manually recovered.

First Contact messages often bring new business or new opportunities. Typically the injury to your relationship with the sender and to your reputation would be greater as a result of a First Contact lost message, then for what it would be for other types of lost messages. Further, First Contact lost messages are probably going to cost you more in terms of lost business and lost opportunities then the other types, so you're probably going to be less tolerant towards them. Fortunately, it is very easy for "Message Keys for Outlook" to avoid them, or a least to identify and recover them.

If discovered, these are the types of lost messages that people remember, that instigate support calls, and that people talk about.

Replies

Reply Messages are part of a conversion or the continuation of an existing relationship. They are the easiest lost message to avoid, because after all you wrote to the sender, so it shouldn't be any surprise to your spam filter that they have now written back. You are also more likely to find and manually recover this type of lost message yourself - as you are are typically expecting a reply, and will go looking for it when you don't receive it.  Perhaps fear of this type of lost message is the most common reason for a person to frequent their Spam folder - which of course exposes them to all of their spam - which does somewhat undermine the value of their spam filter, but that is another story.

Solicited Bulk Email 

This group includes email publications, Newsletter Subscriptions, Automated Confirmation Messages, Validation and Activation emails, and messages from email based services such as Lyris' Content Checker , or Google's Alerts service. Spam filters that utilize user collaboration often find these difficult to avoid as often the same message is sent to multiple users, some of which may incorrectly report the message as Spam.  Many user routinely frequent their Spam folder to recover this type of message, so they are sen by many as just a minor inconvenience - in fact they ca be a blessing as a person may find other more important types of lost message while checking their junk folder for their newsletter subscription.  The problem of course is that - whenever you check your spam folder, you are being exposed to all of your spam -which kind of makes you wonder what you are running a spam filter for in the first place.