Does anyone from here knows a possibility/method or pluging which will allow me to add tags/keywords to emails that I receive in Outlook 2007?
It's called Categories in Outlook 2007 and it's built in. I use it all the time - I have a few standard categories that I can right click the email to add, or I can type in new ones. If I also flag the message it appears in my Tasks, sorted by Category. Excellent functionality.
Using the built-in search I can also specify categories to search within by clicking or typing
in the search field..