http://www.wolfram.com/mathematica/new-in-9/
The new Wolfram Predictive Interface, which dramatically improves navigation
and discovery of Mathematica's functionalityHighly integrated units support, including free-form linguistic entry, conversions
, and dimensional consistency checking across graphics and numeric and symbolic
calculationsNew graph and network analysis, including a built-in link for Facebook, LinkedIn
, Twitter, and moreDirect CDF deployment with live data at runtime and other enhanced features
with Mathematica Enterprise Edition, plus preview modes that emulate Wolfram
CDF Player and Wolfram Player ProMajor new data science, probability, and statistics functionality—including
survival and reliability analysis, Markov chains, queueing theory, time
series, and stochastic differential equations3D volumetric image processing and out-of-core technology that scales up
performance to very large 2D and 3D images and video
Integrated analog and digital signal processingBuilt-in symbolic tensors with support for arrays of any rank, dimension,
and symmetry
Highly customizable interactive gauges for dashboards and controlsSystemwide support for automatic legends for plots and charts
R fully integrated into Mathematica workflow for seamless data and code exchangeFull client-side web access for exchanging data with remote servers and interacting
with web APIs
Updated look for slide shows with new style templates and background images