Use of Internet filters has increased in households with teenagers in them, but not as much as you might expect.

Of course, it’s still an open question how well filters work at blocking kid non-friendly stuff from a PC’s screen, but some filter is better than no filter. More than half (54 percent) of American families with teenagers use an online filter to limit access to potentially harmful content, according to a new study by the Pew Internet & American Life Project. That’s a 65 percent increase from the year 2000.

Who uses filters? The tendency is by parents who themselves are frequent users of the Internet (they know what’s out there) and who have middle-school-age children. Parents with older children and who are less tech-savvy are, as you might expect, less likely to use filters. But no one is really fooled – both teens and parents believe that teens do things on the Internet that their parents would not approve of.