Not even outdated - just incorrect. There have been proprietary tools longer than there have been computers, it's the point of patents - grant a monopoly on you

Not even outdated - just incorrect. There have been proprietary tools longer than there have been computers, it's the point of patents - grant a monopoly on your proprietary tool for X years in exchange for making it's workings public knowledge. Even patents aside, why wouldn't this D2 thing qualify as: COMPUTING a piece of software that carries out a particular function, typically creating or modifying another program. (source: google "define tool") While it isn't creating or modifying a program, I'd consider "parsing text in a specific syntax to create a diagram" more like a compiler than a site that just provides information or crud sites with some forms. I'm not entirely certain how where it runs affects it's tool status, but it certainly is a consideration to be made while evaluating it for any particular use case. (also from define tool: a thing used in an occupation or pursuit. and depending on where you stand on the "thingness" of software may also apply here, but that feels diversionary) I can think of quite a few single vendor languages - various IBM mainframe languages like JCL, K, matlab, multiple .Net and MS languages until recently, applescript, etc.