As spam defenses and spammers become more sophisticated, many smart spammers have developed very sophisticated defenses against being detected. One of the spammer's strategies is to quickly and effectively remove anyone from their mailing lists who files a spam complaint (until they want to get revenge, and then they use these "remove lists" differently). This is generally (although not always) good for the person filing the complaint, but it is bad for spam defense in general, since these activists are the only ones identifying the problem. By removing the "trouble makers", spammers too often slip "under the radar" and appear to be legitimate senders, even though the majority (or entirety) of the victims don't want the mail (they are just the ones who don't bother to make waves).
In the past, SpamCop has attempted to clean outgoing complaints of any identifying information (codes which spammers use to figure out who is reporting them). However, it has become plain that the only way to really sanitize the reports is to not send them at all. So that is exactly what we're going to do. SpamCop now offers new and existing users an option to withhold almost all data - registering reports in SpamCop's database, but never sending reports to the "ISP" (all too often, the spammer, or a spam-friendly host).
Some users may wish to file reports, and get themselves removed from any spammer's list who is sophisticated enough to remove them (and take the risk of retaliation). Others may wish to take advantage of this SpamCop feature and become a "mole." SpamCop will then only give information about these "mole" reports as aggregate and unspecific totals. Truly conscientious ISPs will still find some value in these aggregate numbers, while the less ethical won't be able to "work the system."
It is recommended that users pick one mode or the other and use that exclusively. Otherwise, you are likely to get the worst of both worlds. Users may set their account to "mole" status under the "Preferences" menu item, "Reporting Preferences", "Spam Munging".