A new report has said that it is now easy to let your sexual partner now if you have unknowingly exposed them to the risk of a sexually transmitted disease.
The report said that some 30,000 people have used an Internet service that allows then send of alerts to their partners with the click of a mouse.
"This has been an innovative and effective way for us to enable people to communicate with their sex partners," said Dr. Jeffrey Klausner, director of STD prevention and control services at the San Francisco Department of Health.
"We're living in a new world of Internet communication," Klausner said. "Most people are online every day. This Internet communication tool affords people a way to send a message anonymously." Many e-cards warned about gonorrhea, syphilis, HIV and chlamydia.
The details appear in PLoS Medicine.