One of the RPG's im working on,  I chose to put out in the format of a rules viewer program instead of a PDF.  This means a program you launch and click around through menu's.  The rationale I posted for this was originally put as such

On the matter of why I chose to put Piecemeal in an .exe format. There are a few different reasons why that is the case. The first is that Piecemeal (unlike Adventure Party!) does feature a lot of rules. A large peeve of mine is the difficulty in cross referencing rules to other pertinent rules inside of RPG books. The ability to click to a term as it is mentioned (in case you have forgotten or simply not read about that term yet) is a large feature. Piecemeal is also designed as a plug and play system, so that you can remove bits and without too much fuss..add them into your own game system of choice. The compartmentalization offered by an interactive program allows for quick reference during play (as laptops are becoming almost a standard in many game tables). The last reason is to aid with virtual tabletop gaming, platforms (Some free some not) that allow old spread out gaming groups (such as my own) still play classic pen and paper role playing games on our computers, thousands of miles from each other. PDFs of the size required by Piecemeal are unlikely to be printed out, so any viewing of the rules would have to be on a computer regardless. For a shorter RPG (such as Adventure Party) where it is not rules heavy, and where printing is a viable option, I chose to put it in simple PDF format.

On the matter of security

While I understand there is a perception that PDF's are safe, as a not of profesional (from my paid job) note, they are not safe. For anyone with an older reader, a third party reader, or who upgraded to Acrobat Writer, PDF's can contain viruses and there are many counts of this occuring.

On the matter of indexing

As a technophile I may have a bias here, but it is a simple fact that no print index can ever match the possibilities of a computer for cross referencing. This is similarly to how no Oral Historian can ever hope to match the possibilities for permanance of a written document.

In both cases the individual executions may be off, but technology simply offers too many new options.

No index, Icons or perfect document layout in print can match the ability to cross reference computer files. I cannot have pages 7, 37 and 72 all laid out next to each other in a book without scissors or multiple copies.

Note, that doesn't mean a computer viewer will do this right, only that it can. An amazing print layout specialist will beat a bumbling computer programmer(me). But assuming equal caliber of indivuals, print cannot compete.

On the matter of laptops

Laptops are becoming the norm, and as time goes by they will only become more so. You mentioned a $600 dollar laptop, when I finished highshool they were $2000, and now I picked up a work laptop (new) last year for $300.

I don't see this shrinking as time goes by.

Furthermore in PDF form one is already assuming the reader has a computer. Even if its not a laptop, its a rules program. Moving to the computer to quickly reference a rule is not a huge issue compare to digging through a pile of books and flipping through the pages. And if you do have a laptop its much quicker than a book.

On the matter of revisions

Source Code is still in the end a single document on the authors computer, more so it seems to more accepted to have different "Version numbers" of software.

As a Mac user, your Windows based application RPG would be unusuable. However, thats only what 5% of users or something?

There are still emulators that free, quick and easy.  So in that case its not much more different than downloading Acrobat before opening a PDF.

That being said getting some more compilers without investing money (ie legitimate free compilers) is something Im looking into. 

My example is a bad one in terms of actual product, Im still getting used to programming without being able to install frameworks on the host PC's to enable more functionality.  But as a concept piece I think it shows promise to grow into (if only I had more time, something Im sure all developers think)

Security would still be a problem.  It's not difficult to defend against a pdf virus (even if I would have gladly avoided even this hassle: thanks, software houses that think to make our life "easier" by putting us at risk. I still remember the times when "you can get a virus by reading emails" was a joke...), It's not on the same level as running a executable file that could host not only visuses, but even trojan horses, too. 

Add to this that installing something could cause problems even if there is no malicious intent: how much I trust someone's programming ability? Will I have to reinstall dome vital part of the operative system that will be overwritten by the installation files?

And do I really need another program icon in my PC?

I should be really motivated to do this. I would have to really want to use your game. Curiosity would not be enough. Are you a famous designer? It's your game something mind-blowing innovative?

I am not asking these question to harass you, but because these are the questions everybody will think about. Do you have a good answer to them?

To amplify what Moreno said, you'll have to also address long-term usability. I have PDFs from 1996 that I still use (Neo-Anarchists Guide to Everything Else). I have software from 1996 that I would use if I could, but I can't. It doesn't run any more, and the authors either aren't in business any more, or aren't interested in updating it.

I'm one of those authors. The technique you're describing--writing custom viewer software to present books in "innovative" formats--was popular back in that time period just before the web. A ton of them came out on HyperCard, for example. Every once in a while I fire up the old Mac SE/30 in my office to show off The Warsaw Project, an "interactive book" made by a trio of faculty at our university. I have to, because the "book" doesn't run on anything newer. It actually started to fail about a year after we released it.

More recently, the same impulse was behind formats such as ATRAC in music distribution. Even with Sony behind it, that format failed in favor of more widely available formats.

As a potential purchaser, I'd be very leery of buying something in a custom format that will fail, when other formats exist and are widely available.

Now, you can still get my attention with documents that use a viewer likely to fail as long as the data's in a more long-term format. I had no problem spending a lot of money for the Dragon CD-ROM archive. They wrote their own viewer software, and that viewer software never worked on my platforms, but the documents are in PDF and I can still read them.

The feature you mention--clicking to cross-reference--is easily available in HTML, and HTML+CSS gives you amazing layout options nowadays. (You can even write your own viewer using public code bases such as Gecko or Webkit if you want to provide a sandboxed environment. Add in JavaScript (take a look at SproutCore, for an example of a detailed framework) and you can layer even more dynamic functionality without triggering my "why is this book not readable" flag.)

Which isn't to say that you shouldn't do innovative things, but you're going to want to be clear with regards to "why is my book not a book" if you want to sell it as custom software.

To expand on what Jerry said (hey Jerry! Long time no see!), if you want to go this route, it's the format, not the software. PDF succeeds (well, one reason) is that the standard is public, if not open. Your best bet would be to find similar standards that have some traction and write to those.

I can think of the following:

Microsoft Compiled HTML Help has a lot of the features you want in terms of hyperlinking, indexing and so on. It even has readers on other platforms (e.g. Chmox).

One of the many eBook formats. Each of these will no doubt have one or two of the feature you want. One might even have all of them. I'd look at Monipocket, TomeRaider and eReader first.

So far you haven't made a compelling case to use something besides PDF.  PDF allows hyperlinking, and it's pretty easy to do in any word processing program or layout software.  PDF also supports javascript, so you can make a character sheet with calculated fields without any real problem.

I write software for a living, and I love gaming software, but I don't see the point of writing software that duplicates, poorly, features already existing in other more standard formats.  Also, distributing and supporting software is a much bigger pain in the butt than you realize, if you haven't done this before.  PDF, on the other hand, doesn't require any support for the technical aspects of it.  That leaves you free to focus on supporting the game instead of the delivery mechanism.

If all you really want is hyperlinking, I think you might be better off distributing the thing as a web site that sells access.  Contact me via email (see my profile) and I can show you some nice tools for doing that aside from rolling your own.  And rolling your own might be fun, but this problem has long since been solved.

I concur that the specialized reader software is a bad idea. Acrobat has its warts, among them that Adobe changes the list of advanced features it supports with every new version, but for a document that virtually any computer can read and display properly, it's the way to go. Viruses or other malware are always going to be with us, and very, very few people will refuse to use Acrobat because they are afraid their computer will catch a bug from a pdf. I suspect they would be more afraid of a custom piece of software they have never heard of (like your display program).

Greg
BTRC