Although Google doesn't reveal too many specifics of their updates, it seems that they've made Hummingbird to be all about improving conversational search. It does this by focusing less on the individual keywords in a query, and addressing the question in the query as a whole.
For example, if someone asked "where can I find places near me that serve deep dish pizza?" the old algorithm would pick out keywords like "pizza", "places", and "near" and might yield results from deep dish pizza restaurants to grocery stores that sell frozen pizza. Hummingbird is addressed to fix that, and might even use information on previous searches, your current location, and your G+ profile to make it more personalized. Additionally, after you make your pizza search, if you were to ask "what about ones that are open now?" Google may be able to display results for locations that have specified their hours and are open.
Ideally, this should help local businesses gain exposure to more relevant customers, but only if they have local listings set up properly in Google Places and other local business directories like Yahoo Small Businesses. I would highly recommend small business owners to take a look at getlisted.org to see how their small business is currently listed in local directories, the what improvements can be made, and where they are not listed yet.