I had used this tool in the past, then forgot about it. Recently I have been annoyed by the duplication of contacts on my phone (which is connected to Outlook and to my iPad) so decided to hunt down this software again. Within 5 minutes of installing the Outlook plugin, the software asked me if I wanted to add two people to my contacts – I would have thought they were already in there!
While you can likely configure your email software to automatically add all emails you receive to your address book, this tool does something stronger than that – it analyzes signatures for phone numbers, addresses, etc. and uses that to further update your contact!
Give Evercontact a try – it’s free!
Update for 2019: Evercontact is no longer free but they do have a free trial and it remains an incredibly useful tool!