Surely, InDesign Server has made a huge impact on the web2print market over the past few years. Ours in not at all the only product with a large proportion of InDesign Server based features. But it's important to remember that it is not the only possibility for web2print applications.
Variable printing templates
InDesign Server and the FLO Suite extensions on top of it allow you a lot of freedom in templates. But that is not the only way to embed templates in a web2print solution or a database publishing workflow. PDF templates have been part of our solution for quite some time now, in response to some of the limitations of InDesign server in certain cases. And next to the PDF templates (easily configured with variable data on top of previously created PDF files), you alwas have the possibility to start from scratch with a script. This way, any logical output is possible.
Stock orders
But not all orders in a W2P application need to be template-based. A lot of web2print tools have been created in the past without the use of InDesign Server or other types of lay-out engines. The handling of stock orders, for example, typically does not require the use of any type of templates. Existing materials can be put online, and don't need to be personalized. If a preview is needed, it is often uploaded to the digital asset management system as a PDF file.
Pre-existing (static) materials
Similarly, you can set up printing on demand solutions without the need for templates. These can be stored into assetFLO as highres PDF files, and can be presented to the end users in the web-to-print website as lowres previews. End users order these as they need them, and the PDF files are sent to the MIS as an order. All of this requires no personalization at all.
Online corrections
One thing that can't be handled without InDesign Server is online corrections. The workflow part of that type of application (putting jobs into different statusses, so each person in the lifecycle knows what to edit) is no problem without InDesign. But editing artwork requires the engine. We have actually contemplated creating a variation that would be completely PDF based. But without the graphical engine of a desktop publishing tool such as InDesign, the advantages simply are not big enough.