Online e-mail services have severely gimped auto-forwarding
Storing e-mails on the mail server issues
I recently migrated all of my e-mail from Gmail to Outlook.com which was fairly painful. I had to re-organize all of my e-mail into folders in Outlook.com (10's of thousands of e-mails) and it took me nearly a week to get them all imported and re-organized properly. The lesson I learned was that if I want to save an e-mail permanently, perhaps saving it online in the mail server is not the best idea. Saving a copy permanently locally via a Outlook data file or something is not a proper solution for me either. Over the last two years I've moved from Mail.app to Outlook and then to Airmail on my Mac. I also dualboot OS X and Windows 7, so I need something that allows me to maintain access across both platforms. Storing it permanently in my mail client does not resolve that issue.
The answer? Store them in 1Password and Evernote.
1Password
Web-sites that I sign up for, I tend to keep the sign-up confirmation e-mails so that I can go back and check out what sites I am signed up for (sometimes I am bored and can't remember all of the sites I'm registered at. I find nice sites that I had forgetten about this way). Instead of saving these on the server, I can store the login information into 1Password and then just delete the e-mail. That provides me with a record of the web-sites that I am registered at. I can expunge a lot of my archived e-mails just by performing this step.
Evernote
This is probably the most painful to get migrated initially, but it also provides a great cross-platform solution to store my e-mails. The e-mails that I want to save I will just forward into my Evernote accounts e-mail address. Saving my current archive isn't to big of an issue compared to maintaining it though.
I am thuroughly surprised at how horrible rule systems are on the mail services. Gmail doesn't appear to have any kind of rules other than just auto-filing. Outlook supports auto-forwarding, but it is serverely gimped. I can only forward an e-mail to a specific e-mail address, without being able to edit the header or body. It would be really nice to tell Outlook.com to auto-forward all e-mails from my Dad to my Evernote e-mail address. I could append to the subject the notebook that I want to store it in (E-mail archive) and then apply a tag called "Dad". This would let me go into Evernote and select my E-mail Archive notebook, filter by my Dad tag and instantly see all of the e-mails my dad has sent me.
Unfortunately, I can't do that just yet. Outlook.com's auto-forwarding system is to weak and doesn't have decent options. I looked into my current mail client, Airmail and can't find any auto-forwarding rules within it either. Apple's Mail.app does do forwarding, but it does not let you append content to the subject line of the e-mail it forwards. You can only pre-append text to the message body which does me no good.
So I guess the next step in order to get this working is to dig in and learn some Apple Script. My goal was to find a solution that was not ran locally on my machine. Local solutions requires the machine to be online all the time. I wanted a cloud based solution but have yet to find one.