Thanks for your reply.
I think this could be a fun project.
It looks like setting up a Node.js server is not very hard.
I was thinking of setting up a simple scene that multiple people can interact with. In the beginning I am not worried about login authentication.

Your page here: http://naviris.ru/b4w1/dubina/dubina.html
How can multiple people load the same page and all be able to interact with it? Like a chessboard. The position of each chess piece could be logged by the server and anybody who loads the page could see current positions and change them.

Question about Cordova: Do you think that would be better then a web app running in the mobile browser? Could a Blend4web app pull geolocataion?

I just watched this video with Kirill Petryaev
It opens a lot of possibilities. I am currently using Blend4web to produce a weekly updated 3D model acquired by drone photography for a large industrial site.
This 'mulitplayer' concept opens the possibility of a persistent 3D space with realtime equipment positions and inventory locations. The 'players' in this model would be mobile devices inside moving equipment running the client.
I have been doing this on a small scale for two years now. An app running in a loader counts what it moves by using GPS and uploads to a web app running on Google App Engine. Then a spreadsheet automatically loads the table of data from the site online. So the user just opens their inventory spreadsheet and the data is magically there.
If anybody would like to collaborate with me on this I would be happy to share with the community. Developing a good tool-chain like this could work out very will for Blend4web gaming and commercial applications.

I am hoping to get further information to help me replicate the work of Kirill Petryaev. In the meantime, I am studying up on AJAX and NodeJS, either of which might work for this.

I use multiple drives. I put the SDK on a different drive and everything is fine now. Some kind of ghost in the machine.

Thanks Yuri,
I will keep working on it and post my results. It is something to do with my PC as all the same programs work fine on my other PC.

I removed the addon from User Preferences/Addons. Once I did that I could no longer get the Blend4web addon to appear in the User Prefrences/Addon menu. User Preferences/File/Scripts is set to the SDK.
I have deleted blender preferences from User/appdata/roaming/blender. Reinstalled Blender and restored Blend4web SDK from back up zip file. Still can't get the Blend4web addon to show up in User Preferences/Addons. I must be missing something.
Can you think of any other files I can wipe to get things back to default?

Ya, the server is running, here is a quick video of the process:
https://www.dropbox.com/s/t84odt5msybv6j5/bug.mp4?dl=0

I have tried it on a different PC with all the same parameters and it works fine. I probably have something tangled up on the machine. I will try removing the addon in preferences and putting it back.

In the Project Manager, after filling in the options , I hit the Create Project button at the bottom and get only a blank Page, (see attachment). A similar thing happens if I try to export a project (like a stock project). I have Java on the path if that makes any difference. Running Win 10.

I should also add that no new files show up in C:\blend4web\apps_dev

Very nice. I have been meaning to work on a good pre-loader.

Well, there are a number of features that rely on visual programming. That is logic nodes that require no coding.
Here is a video that shows an example: https://www.youtube.com/watch?v=i5EWCOuxMjQ
Here is a website I am working on that uses logic nodes to navigate scenes: http://valenciawetland.com/env.html
That being said, with code you can do much more. The list of logic nodes and their functions seem to grow with each update but we can always accomplish more with code.

Keep in mind, that though this feature is not in the no-code HTML export, you can do it with JavaScript code.
See this example: https://www.blend4web.com/en/demo/tut_jungle_outpost/
This example project can also be found in your SDK