Online help is a part of Windows full of dead-ends and back-alleys. I’m not going to attempt the story in detail here; but it goes back many years. By online help I mean local help of course; in ancient times the word “online” meant something on your computer as opposed to being in a printed book.
The first help engine I remember was in Windows 3.x, called WinHelp, and used .hlp files. It was well-liked, but authoring the files was an arcane process involving Word, RTF, a help compiler, and a certain amount of black magic.
In 1997 Microsoft replaced .hlp with .chm (compiled HTML); its initial efforts were less good than the old .hlp, but this evolved into a decent help engine despite one or two quirks.
After that it gets messy. In 2001 Microsoft announced Help 2, still HTML based but with all sorts of improvements. It was used by MSDN and in Visual Studio; its viewer is the Microsoft Document Explorer. However, and despite the help authoring tool vendors getting all geared up for Help 2, Microsoft announced in 2003 that it would not be made into a general Windows help engine, but only used for Visual Studio. Since then Help 2 has had a curious status; it is possible to author for Help 2, and those building Visual Studio extensions have needed to do so, but it has never replaced compiled HTML.
There was a similar story with Vista Help. Microsoft built a new help engine for Vista but drew back from making this available to 3rd party applications. In fact, there is a rather wonderful tool called Guided Help which lets you include application automation within Help, complete with “show me” and “do it” functionality. You can get the Guided Help SDK if you know where to look, and it works, but the project was mostly abandoned. You are still meant to use HTML Help 1.4 for your own applications.
Now Microsoft is talking about Help 3. Microsoft’s Terry Clancy mentions it in an informative post about Visual Studio 2010:
Visual Studio 10 will come with a completely re-engineered Help system that introduces a new flexible, standards based Help framework which will ultimately be used in other products beyond Visual Studio. Help3 is a help system replacement for Microsoft Help 2.x . This new help system will be easier to produce content for, and will interfere less with Visual Studio itself. The standards based approach delivers not only a much better local experience but also a seamless transition to an online web browser and with infrastructure and tooling much more consistent other Visual Studio and internet technologies.
Will Help 3 ever replace the seemingly immortal HTML Help 1.x? Place your bets.
In practice, desktop help is less important than it used to be. Online help now means the Internet; or users just use Google.