http://msmvps.com/blogs/laflour/archive/2009/03/06/sharepoint-tip-19-do-you-know-when-to-use-web-services-and-when-api.aspxSharePoint provides you two models for development – Web Services and API for object model. But very often developers are a bit confused about what to use and when. SharePoint API provides access to all pillars of SharePoint – advanced functionality viaenCommunityServer 2008.5 SP2 (Build: 40407.4157)