Automattic

You can used this technique to register on sites and forum. To name a few → digg, myspace, newsvine, 9rules, blogger & msn etc.

Gravatar sign-up process took less than 5 minute to complete and they don’t burden you with filling form chores (i.e: address, newsletter subscriptions, marketing questionnaire). So we pick Gravatar Web services for this guide.

Requirements

You must have the following email.

1. Gmail or Google Aps Gmail

Gmail Plus-Addressing Features

In brief, Gmail services has undocumented plus-addressing features (+) since early 2004. The plus-addressing features is mostly used for writing self notes, email filtering and mapping (google maps).

“Gmail never announce this features (beta forever) as there is no official documentation at Gmail Help Center.” — Anon [...]