Jillian Prystupa, of Massapequa, N.Y., who is studying to be a history teacher, says she thinks websites should warn visitors if their information is going to be stored or bought and sold.

The Information on School Websites Is Not as Safe as You Think

Some tracking scripts may be harmless. But others are designed to recognize I.P. addresses and embed cookies that collect information prized by advertisers.

nytimes.com