"Interactive television has been an elusive goal almost as long as Alex Thompson has been alive. Although various schemes for real-time viewer feedback to TV programs have been demonstrated, none has secured a market foothold. A new system promoted by Thompson’s company, Mixed Signals Technologies, could turn this dismal history around. This system combines WebTV and Echostar set-top boxes and relies on program encoding equipment from Mixed Signals, which Thompson started in 1997. Mixed Signals inserts data for interactivity into the interval between broadcast video frames. Having developed the software, marketed as TV Link Creator, Thompson merged her firm with Ultech, which makes video-encoding hardware. The resulting ITV Dataflo System is becoming a standard tool for program developers, adding interactivity to TV game shows. Sony/Columbia TriStar Television, producer of ""Wheel of Fortune"" and ""Jeopardy,"" liked the technology so much that parent company Sony Pictures is investing upwards of $13 million in Thompson’s venture. Says Andy Kaplan, executive vice president of Columbia TriStar: ""Alex has proven herself to be a leader in developing a cutting-edge technology which, we believe, will have a significant effect on our future business."""