Okay here it is :

I have built an c# console app that downloads email, save attachments , and stores the subject, from, to, body to a MS SQL Database.

I use aspNetPOP3 Component to do this.

I have build a front end ASP.NET application to search and view the messages. Works great.

Next Steps (this is where I need help ):

Now I want my users (of the asp.net app) to reply to this message send the email to the originator, and tread any additional replies back and forth on from that original message(like basecamp).

This would allow my end user not to have to log-in to a system, they just continue using email (our users can as well).

The question is what should I use to determine if messages are related? Subject line I think is a bad approach.

I believe the best method i've seen so far is way basecamp does it, but I'm not sure how that is done, here is a real example of the reply to address from a basecamp email (I've changed the host name):

[email protected]

Basecamp obviously are prefixing the pre-pending a tracking id to the email address, however , when I try this with my mail service, it's rejected. Is this the best approach, is there a way I can accomplish this, is there a better approach, or even a better email component tool?

Thanks,

Mike