On print-friendly versions of web-pages

I don't usually plug anything, but...

I have been working my way through my to-do list as one does in idle moments and came up against an item I have sent to the back of the list several times. Readers want a printer-friendly version of the site's pages, and I was not looking forward to sorting that out. I no longer have external funding for a developer to do it, and I could envisage that my shaky grasp of javascript and/or css would lead to many hours of frustration, not to mention the pain of inserting the scripts into every one of 500-odd pages if they couldn't go into a server-side include...

Of course I googled for solutions, and there were many of the kind I had envisaged, and then there was this one! A snippet of code, much like the "embed" instructions for YouTube or SlideShare, to copy and paste into the standard page footer (there are only three of them across the sites) and it was done! Ten minutes max. I went for a walk in the park in the time I had saved, grinning stupidly (until it started to rain, but even that saved me from having to wash accumulated crud off the car...) Sometimes things do work out!

There's another variant, too, of more interest to readers than webmasters; you can simply drag a button from the site to the browser toolbar (it's a bit more complicated for IE apparently), and there is an instant widget to create a printer-friendly page from whatever you are looking at.

Except that I don't understand what the business model can be. The service is free. You don't even have to register. There are no ads (so far, and it appears to have been going for several months), and I wouldn't have found it but for my fairly specific search. Can it survive?