An interesting concept and good for recalling meetings and having the ability to exchange information. The application is limited, however, in not being able to search for a contact across multiple accounts and not just Twitter or e-mail, but also FB and LinkedIn, for example. For instance, some business card apps allow for auto search in LinkedIn. Surely, something similar could be done here.
Hashable is the best way to remember where & when you met someone. It organizes contact info and keeps track of who you're meeting. It can send digital business cards, make auto-intros and generally keep your address book handy and updated in your smartphone.
Disclosure: Yes I work for this company, but only because I started using it and realized that the product was hella useful. Just sayin'.