The big opportunity offered by FM WebDirect is the great simplification of deployment that it offers.
In the past even to enable someone to trial your solution they had to install FMPro first - a real hassle - or perhaps FMGo - which was easier before they could do anything.
Most folk are now so used to getting apps from the Store that the idea of needing several bits of software on their device often from different sources before they can ever try something is quite unwelcome and a significant barrier to new users.
The fact that anyone, on any platform, except currently perhaps in Safari on iOS7 under FMS13v1, can open your Filemaker solution in their Safari, Chrome or Internet Explorer browser and use it pretty much as if they had FM Pro on their device is a great opportunity - for us all to expand the user base.
However, this does mean that we now probably need to think about developing fast and efficient easy-to-use solutions specifially for FM WebDirect - which will be attractive to these potential new non Filemaker users.