According to Wikipedia, Web 2.0 is a phrase coined by O'Reilly Media in 2004, and refers to a perceived or proposed second generation of Internet-based services—such as social networking sites, wikis, communication tools, and folksonomies—that emphasize online collaboration and sharing among users.
In regards to spam filtering, I need a term to describe the method of soliciting user-feedback and classification of messages as spam or non-spam. So, to suit my own purposes, I will define Two-Point Filtering as the process of end-users classifying their email as spam or non-spam (like a feedback loop) and then using that classification as a primary mechanism for spam filtering. There is no additional checking on whether or not the user classification is valid. For example, if a spam filter uses a user-classified feedback loop to train their filters without doing any additional quality control, I will refer to this Two-Point Filtering. In real terms, a Two-Point filter might be a plugin in Outlook. When users click on the spam/non-spam button the message goes straight into a Bayesian filter in order to train it.
Obviously, I have made this term up out of necessity (if there is a proper way to describe it please let me know... or maybe don't and let me think I've invented a new term). The concept will be central to my point in my next post.