Web based GIS, Past and Present
We have directly or indirectly been involved in Web based GIS for quite a few years now, and it is quite interesting how the approach has changed over time. The early days saw the reliance on client based plugins and has slowly progressed to no reliance on client side plugins and virtually no reliance on server side solutions.
Unfortunately, in South Africa, there are limited WMS servers available. I am confident that this will change over time, but, to overcome this in the interim, as GIS consultants, we are required to setup our own services using server side software. Fortunately there are lots of open source and reliable solutions to do just that. the most widely used solutions are; Sharpmap, MapServer, and GeoServer. All three of these options are open source and, with the exception of Sharpmap, can be run on Windows or Linux. Add Tilecache to the equation and you have a truly managed and fast solution.
Where to From Now?
The big question is, where do the big commercial products fit in? Personally, I think unless there is a major shift in thinking from these big corporate's, they will notice a marked drop in sales going forward. Mapguide has already taken the bull by the horns by going open source, and ESRI does not sponsor the FOSS4G conferences for the good of the GIS community! They are keeping an eye on things! Big corporate's needing to manage large cadastral datasets over the web may still have a requirement for using ArcIMS or MapXtreme, but then again isn't that what ArcGIS or Mapinfo are for?
As for Open Source GIS and South Africa, things could not look better at the moment. South Africa is the host country for the FOSS4G conference, and we can already show the rest of the world how we are making commercial success purely using open source products. I am by now means an Open Source fanatic, I still run windows and MS office..our mail is still hosted on exchange and our server is still Windows Server with IIS...but, I am definitely finding that in the GIS world open source products are noticeably leaping ahead of equivalent commercial products, wether it is web GIS or desktop based analysis using Postgres with the PostGIS plugin! to all involved I would say keep at it, you are doing the GIS community a favour.
for an example of Openlayers in use, have a look at our Openlayers based site - Mapexchange (ignoring our restricted bandwidth in South Africa!).