Paired t-tests are a form of blocking, and have greater power than unpaired tests when the paired units are similar with respect to noise factors that are independent of membership in the two groups being compared.
The service, by the way, is called AOL My eAddress. AOL says it supports .com or .net domains, up to 100 e-mail identities per domain, 2 GB of storage, spam filtering, and open mail clients such as Outlook and Thunderbird through the IMAP protocol.
To use AOL Search, type a word or phrase that describes what you're looking for in the AOL Search window, and then press Enter on your keyboard or click Search. The AOL Search window will appear every time you sign in to your AOL Desktop software, unless you disable it.