I'm looking for an easy way to keep track of e-mails in Outlook. I'm hoping someone knows of an add-on where I can select multiple e-mails, and either right click and have an option, or hit a hot key to group the e-mails. They don't have to stay together, but I'd like something to come up when I open one of them, showing me all the related messages.

Some reason why you're not simply making a group folder and moving the messages to it?

You can use the Rules capability to set up a rule that moves mails with a common attribute into a folder.

I know you can make separate folders, but if I made a new folder for every bunch of e-mails with a specific topic, I'd have thousands of folders...

I believe you can save search criteria so you can run searches again.

In 2007 and perhaps prior versions you can view and group by conversation and you can also find related messages from an open message. I don't know of anything that behaves as you indicated and for such an add-on there would be the problem of tagging the messages and storing the metadata somewhere, probably in a database if you have thousands of messages. I suspect you're looking at some sort of archiving solution to do what you want.

I've tried grouping by conversation too, my only problem with that, is people don't always use the same subject line when referring to a project, or they refer to several projects in one e-mail.

Thanks for the tips guys... I don't think I'm going to find what I'm looking for though :(

As Scott and Sleros have eluded to, try the Search Folders. This is where you can create and save searches. Each time you open the saved search, it performs the query again so that it is always updated.

Also, within Contacts, open a Contact with an email address in it. Select the Activities tab and you will see all items related to that person whether they were part of a scheduled meeting, task or email (both sent and received).

When a message is opened, you can select Tools and then Find All and choose Related Messages.

As you mentioned, all of these things are limited unless you and your colleagues use a defined set of key words to enhance the searcheability of your content. We use a product call Symantec Enterprise Vault. It saves a copy of every single email to/from every employee into a vault and it is all indexed into a search engine. Within a matter of minutes, we can perform Ad-Hoc searches on over 1.5 million emails. It also performs rules based archiving of emails, files and Sharepoint portals. This product also has a legal discovery component that aids in the compliance of Sarbanes-Oxley laws.