
Carriers and manufacturers have exploited Android's "open" platform as a means to add their own features in an attempt to differentiate themselves in the marketplace. Aside from often creating usability problems, these unnecessarily customized versions of Android have delayed firmware updates for older devices, and even resulted in carriers abandoning phones entirely. Presently there are eight versions of Android application framework API that a device can support. With no clear upgrade path for many devices due to UI extensions like HTC Sense, the platform is even further fragmented.
Google's official line on the topic of fragmentation is that it's a non-issue. According to Android's Dan Morrill, "Fragmentation is a bogeyman, a red herring, a story you tell to frighten junior developers. Yawn." Yes, Dan, were Google to enforce their own Compatibility Definition Document with carriers and OEMs, that statement might even be true.