SpyBot-S&D searches your harddisk for so-called spy- or adbots; little modules that are responsible for the ads many programs show. But many of these modules also transmit information about your surfing behaviour and more to the net. If SpyBot-S&D finds such modules, it can remove them - or replace them with empty dummies in case their host won`t work any more with its bot removed. In most cases, the host software still runs after removing the bot.