As used on PP.SE, "software" actually refers to that subset of software that is useful in enhancing productivity, effiency, and/or organization. (Ie, mind maps are in, video games are out.) Some specific types of software that often fit include:
Keeping in mind, of course, that the specific question has to also fit within the PP.SE scope. Many of these types of software have their own tag, often because there are also analog implementations. So a question about mind maps might be tagged just [mind maps] if the author was open to both software and paper-based answers, but as [mind maps][software] if they wanted answers usable specifically on the computer.