SharePoint 2010 comes with different editions like:SharePoint Foundation:Microsoft SharePoint Foundation 2010 is the basic edition of the product. Its free and comes with the license of Microsoft Windows Server 2008. It has only document storage and collaboration solution. But this edition also have cross-browser support, basic search features, out-of-thebox Web Parts, Silverlight support, new UI features based on dialogs and ribbons, blogs and wikis, and the workflow engine.
SharePoint Foundation has its ability to upgrade from previous versions of Microsoft SharePoint.
SharePoint Foundation also offers all the features supporting custom development, including the Web Parts programming model, the Server Object Model, the Client Object Model, Event Receivers, Claims-Based security etc
SharePoint Server Standard:
Microsoft SharePoint Server 2010 Standard edition is built on top of SharePoint Foundation and adds some features useful for building business-level solutions.
Also it supports Document Sets,content based on audiences, tags and metadata-driven search refinement, people search, and some other social features. It also provides tags and metadata-driven search refinement, people search, and some other social features.
SharePoint Server Enterprise:
Microsoft SharePoint Server 2010 Enterprise edition targets large business solutions and enterprise-level organizations. It has all the features of SharePoint Server Standard also. Also it supports dashboards, key performance indicators (KPIs), and business intelligence features.
It improves search capabilities by offering contextual search, deep search query refinement, extreme scale-out search capabilities, rich web indexing, and so on. It also provides support for Excel Services, Visio Services, InfoPath Forms Services, and Access Services.
SharePoint for Internet Sites:
Microsoft SharePoint Server 2010 for Internet Sites Standard and Enterprise editions. These editions target web publishing sites. They were created to support public Internet scenarios with an unpredictable number of users coming from the Internet, whether the users are anonymous or authenticated.
The Standard Edition for Internet Sites is licensed for publishing a single domain website, while the Enterprise Edition for Internet Sites can publish multiple domains.