Our admittedly unscientific roundup of some of the unmarried tech executives who inspire the most buzz in Silicon Valley and its East Coast counterpart, Silicon Alley, is still mostly men who have a net worth in eight or nine figures. But that could change in the next few years as a generation of hard-charging single women in their 20s (Alexa Hirschfeld of Paperless Post, Hayley Barna from Birchbox or Melody McCloskey from StyleSeat) begin to make their move. Jack Dorsey, co-founder, Twitter and Square Mr. Dorsey, 36, has gone from bike messenger to Internet superstar, net worth estimated at $650 million, all on the strength of a simple idea that turned out to be one of the most intoxicating time-sucks since television.Along with money came the trappings of fame: the Prada suits, the A-list friends (Ashton Kutcher, Alyssa Milano), the long Vanity Fair profile last year - and even hints that he is eyeing a political future. Mr. Dorsey tends to keep his romance private, although he did discuss a recent relationship with Sofiane Sylve, a principal dancer with the San Francisco Ballet, in that Vanity Fair article. "I've learned a lot from ballet," he was quoted as saying. I appreciate the coordination and the discipline.Making something simple is very difficult. Pete Cashmore, chief executive, Mashable Inc. magazine tagged Mr. Cashmore - 26 and with a net worth estimated as high as $95 million - as "the Brad Pitt of the blogosphere." Gawker called him "the planet's sexiest geek." He currently sees Lisa Bettany, a photographer and entrepreneur. And like a matinee idol, he has a sultry air that has even become an in-joke among techies. An anonymous Twitter account called @hotpetecashmore is dotted with tweets like "Am I the only one feeling hot, hot, hot tonight? - Pete." But Mr. Cashmore did not make it on his looks. He started Mashable in his bedroom in Aberdeen, Scotland,at age 19, and for a time some tech insiders joked that he was the "Loch Ness Blogger,"because so few in tech circles had actually laid eyes on him. Those days are over. Mashable now attracts more than 20 million visitors a month, and this year, Mr. Cashmore made Time's list of the 100 most influential people, as well as the Forbes "30 Under 30" list. Matt Cohler, Facebook employee No. 7, now general partner at Benchmark Capital