The basic idea is simple: collapse external storage (and, eventually networking) into a single, software-powered environment that runs on commodity servers.
The potential benefit is two-fold: reduced capex through use of commodity server platforms, and reduced opex through less reliance on storage (and network) specialists.
The market pundits forecast that this category will continue to grow. VMware plays in multiple ways, but so do a bevy of startups.
The realist in me knows that everything has its pros and cons. Enterprise IT is a diverse, complex beast — where does hyperconverged fit, and — most importantly — where does it not?