One of the challenges Adobe face with Apollo will be how wide an audience they can reach in a short amount of time. The golden target would be of course, to reach similar levels of adoption as the Flash Player. However this is a mamouth task and will certainly not happen over night.
The other query that springs to mind is whether Apollo needs that kind of distribution? Are the benefits Apollo offers going to be capitalised by the open public market (E.g. YouTube apps, eBay apps, Amazon apps etc.) that become household names and can be found in every home, web cafe and office workers desktop. Or will the big benefits by drawn by closed audience Intranet and Extranet applications?
Apollo deployment figures will be an interesting one to watch and will be very much influenced by the creation of popular applications. Another consideration for RIA enthusiasts is whether to create a solely online application or create a version for web browser access, a beefed up version for local installation and even mobile specific implementations. The flexibility of the platform should allow for the catering of these different platforms without the need for complete re-development each time. Approaches like this should greatly benefit the adoption rate of Apollo by offering extra sugar for users that try the online versions of applications.