Most major search engines now make efforts to localise search results by default, and mobile search in particular makes use of geolocation data to provide highly localised results.
For example, a search for "hotel Cardiff" in Google will provide results similar to the following:
Similarly, searches conducted on smartphones and tablets with geolocation systems can conduct location specific searches without any additional input from the user:
For obvious reasons, these scenarios present significant opportunities for organisations interested in furthering their interests via search engine visibility. Local SEO focusses on the various means by which websites can be optimised to capitalise on there opportunities, for example by use of Google+ Local and localised social networks like Foursquare.