Well, you can have a local web app (intranet) and a public web app (internet).
If you build for intranet can be used also on the internet.
Also, you can have a client-server app with dummy terminals (Oracle Db plus Oracle Forms), or with an MS network (access DB).
A cutoff point is a budget if you go to a company and the previous app was a client-server, and they do not want to spend money for hardware, it is possible obvious that the new app is going to use the server as an intranet web app or as client sever.
Another cutoff point is what you and your team know, what is your background. If you know C you can write PRO*C and connect with a DB like Oracle.
Another cutoff point is the time of delivery, one year or how many days.
When I was in the University, they said that 70% of IT projects were a failure, so they must pay you according to the delivery parts, and they have to sign the documents of analysis with legal consequences for the software company and the client, and this may be the final cutoff points.
