TiVo ( TIVO) CEO Mike Ramsay said Wednesday he would step down once the company finds a successor.Ramsay, who will retain his post as the digital video recorder company's chairman, thus opens the door to new management at a crucial point in TiVo's history. In recent weeks, the company has announced a number of new business and technology ventures, including one with Microsoft ( MSFT), which TiVo hopes will increase its popularity among consumers and expand its revenue. But last week the satellite operator DirecTV ( DTV) made the long-expected announcement that it will focus on selling a rival product to TiVo. DirecTV, whose distribution of TiVo has been a key element of the company's growth, will be using a box made by a fellow affiliate of DirecTV controlling shareholder News Corporation ( NWSA). The promise of the new ventures juxtaposed with the disappointment of DirecTV's shifting loyalties illustrates the uncertainties facing TiVo. Undoubtedly, the company deserves credit for pioneering the technology of a home digital video recorder, an increasingly popular device that allows TV viewers to easily view their favorite programming on their own schedule and own terms. "We have achieved a tremendous amount since we started the company," read a statement Wednesday from Ramsay, who has served as TiVo's CEO since co-founding it in 1997. "We have had a fundamental impact on television viewing and believe strongly that the company has huge upside potential, in a massive market, going forward. I believe it is a natural evolution of any company to have a transition of leadership as the company grows and matures." But, as technical pioneers such as Netscape (in the world of Web browsers) and Hayes (in the world of modems) have already illustrated, developing an eponymous technology is no guarantee that a company will develop a sustainable, profitable business. And TiVo is far from persuading the market that it will meet a fate different from that of its illustrious predecessors.