The average IT manager probably doesn’t care about who’s in charge of their key vendors — until strategies abruptly shift, products get discontinued and service or support options change.

Many of the key leaders in IT style themselves as visionaries, offering customers and partners a bold mission statement about the future of the IT industry and how their particular firm will shape it. In some cases — Steve Jobs comes to mind — these leaders get a lot of applause and even adoption by their target market. In other cases, management missteps, poorly-performing products and even criminal acts detail the careers of vendor CEOs.

For a look back on how some of the mighty have fallen over the years, visit our slide show, The tech industry’s 10 ugliest exec ousters.