Money.

Companies in the Baltimore and Washington, D.C., regions received $445.7 million in venture capital funding in Q3 of 2013, “the highest level in almost six years.”
According to the Baltimore Business Journal:

The $445.7 million the 53 companies received was the most since fourth quarter 2007 when 81 firms captured $449.5 million in VC funding . . .

On a national scale, software companies received the most venture funding, followed by biotech companies and medical device companies.