Jeffrey Zeldman has posted an excellent piece examining the challenges facing web designers today as they attempt to target an increasingly fragmented set of mobile devices. Riffing off an observation by Stephanie Rieger, Zeldman draws a parallel between the state of mobile web "viewports" today and the fragmentation and lack of standardization web developers faced in the mid and late 90s during the height of the browser wars — before CSS truly came into its own. Unfortunately, the path forward to help web designers deal with the multiplicity of different mobile devices isn't clear yet; not only has it not been forged, but even the right direction is up for debate.
What does it mean for users? For the short term, a situation similar to what we saw in the 90s: a poor experience on mobile devices that can't be entirely blamed on web designers who are forced to choose between multiple bad options and therefore make necessary compromises. However, with some collective action and marketplace consolidation, there is hope that the situation will improve. In the meantime, you'll just need to browse with a sense of goodwill and charity for the lowly web designer who has graduated from having to design for IE6 only to suffer through having to design for literally hundreds of varying screen sizes and browser capabilities.