A better question would be what do you consider dhikr? Because a person can have a rock band and play some songs and call that "dhikr"! And some people actually do this if you know what qawwalis are. Dhikr is confined within shari'ah. Anything that violates shari'ah and props itself up as dhikr is hollow and a sin. Therefore, some forms of "dhikr" that are not found in the shari'ah are a bid'ah and may even be haraam.