Data filters are a piece implant technology crucial for the survival of ordinary sophonts in any extremely information-rich setting, particularly heavily madverted and memed civilizations. A data filter, like ancient "spyware" killing software literally tunes the mind in and out of potentially dangerous information and memes. It cuts out clutter and information overload without interfering with relevant data. Often, this implant works in conjunction with a Data Siphon to compensate for any ebb and flow in data, and prevent any problems that may occur from these variances.
Data Filters are usually powered by very powerful Expert Systems and Simulated Intelligences that have filter abilities similar to that of an S1 transapient intellect, but only in the arena of data and meme filtering. This allows the devices to be small and very portable. Often these are implants of cybernetic, or biotic nature with a DNI interface to a nugget of computronium to house the expert system.
Data filters can also be set to even serve as "sensory deprivation" equipment for giving their users true relaxation. Of course, this is closely monitored for aberrant brain patterns caused by being in sensory deprivation too long.
The quality of a Data Filter does vary greatly, like most cyberware and electronic devices. Some filters may count more as an answering machine, dealing in an informational niche, while others will be massively powerful broad spectrum filters that even edit data sensed in real-time, allowing for vision to have "image not found" style deletions of signs, advertising, sounds, flavors, smells and other forms of information that is potentially hostile. In this type of device, you truly get what you pay for.
Marketing agencies, some sephirotics and polities, corporations, religions and social settings frown on the use of Data Filters. They view them as a threat to their livelihood and control over people. After all, what good is religious preaching if the congregation's data filters are blocking your message as undesirable? For that reason, some groups have banned the devices among their members. Others have begun subversive tactics designed to specifically break or subvert Data Filters and corrupt their control, to enhance their message in subtle ways. Although most Data Filters have "subversion warnings" and corruption checking protections, sometimes a technician is needed to repair corrupted or subverted filters, if the device shuts down in time.