Can Exchange 2007 be configured to do something like this? Or are there any 3rd party applications that add this type of functionality to Exchange?
Afraid not. You can have email addresses with a + in, but exchange won't automatically send these to the right places, you would need to add them as an alias to their account, which kind of defeats the point of having them as throw away addresses.
If we are talking a Plus Addressing, more specifically sub addressing. This convention is known as Sieve Mail Filtering Subaddress Extension Ref: [ RFC 5233 ]. In spirit, What the specification says is that email@example.com will be sent to the inbox of firstname.lastname@example.org. However, because the address is passing an argument - the mail server can perform an action based on the existence of the arg via the Sievel Mail Filter Language. e.g: Kickoff a trouble ticket.
It should be noted that the argument can be alphanumeric. However; you do not want your argument to be longer than 6 characters inaccordance with the specification. Having said all that - this does not seem to be how the industry is using this feature. Instead this technique is more commonly used to create your own DEA account or (disposable email account). The idea being that you will already have a mail client rule set up sends all mail with the argument +site to a folder called W3 Notifications, +signup gets sent to the W3 Accounts folder and +junk -- well you can do with that what you want. As far as I know - most of the major players in the web mail space support sub addressing.
Security considerations are discussed in [RFC5228]. It is believed that this extension does not introduce any additional security concerns.
I hope this helps define the differences between an email alias and sub addressing.
you'll have to go 3rd party but i know a spam filter service called reflexion can handle that. They call it "address-on-the-fly". it allows you to create email@example.com and it automatically knows to forward it to firstname.lastname@example.org. if you see spam coming to that address, you can axe the email@example.com and your firstname.lastname@example.org address still works the exact same.