What is a local search?
A local search is a search done for a specific set of keywords with a location in the search query (dentist SW19 for example). Historically, this search would have returned websites using these keywords within their content, but Google Places changed all that. By registering (and verifying) their company with Google, local businesses could achieve high rankings in SERPs. Since Google displays local results above "other" natural results (see example below).