Below are some changes in SharePoint 2013 search.
- Search user interface improvements include a Search hover panel that provide us with full content previews for Office documents and rich assets.
The Search refinements have also been enhanced with the inclusion of a visual refiner that provides greater context and refinement options.
- Previously in SharePoint 2010, SharePoint has different search products like: Search Server Express, SharePoint Enterprise Search and FAST Search
Server. But in SharePoint 2013 theh have consolidated to a single SharePoint Search platform. The new architecture of 2013 Search has been designed to include the best components of these previous products along with options for better scale out of environments providing both redundancy and performance benefits.
- In Search 2013 you can do administration at both the site collection and an individual site level. This includes being able to define local Search metadata, the sources of Search results and configurable display options.
- Content model changes are delivered through Search Content web parts that leverage the Search index for performance and allow the content to be sourced and shared across site collections.
- Through analytics, in SharePoint 2013
search you will get results like Popular results, My Previous Searches etc.