SPSecurityTrimmedControl or "How to hide stuff from people"
Useful attributes of the control: PermissionContext - against which user permissions will be tested (possible values: CurrentSite, CurrentList, CurrentFolder, CurrentItem or RootSite) PemissionMode - does the user have to meet all role definitions or just one of them (possible values: All or Any) PermissionsString - what permissions does the user need to see the content - can enter some values separated by comma (possible values are from the enumeration SPBasePermissions: EmptyMask,ViewListItems,AddListItems,EditListItems,DeleteListItems,ApproveItems,OpenItems,ViewVersions, DeleteVersions,CancelCheckout,ManagePersonalViews,ManageLists,ViewFormPages,Open,ViewPages, AddAndCustomizePages, ApplyThemeAndBorder,ApplyStyleSheets,ViewUsageData,CreateSSCSite, ManageSubwebs,CreateGroups, ManagePermissions,BrowseDirectories,BrowseUserInfo,AddDelPrivateWebParts, UpdatePersonalWebParts,ManageWeb, UseClientIntegration,UseRemoteAPIs,ManageAlerts,CreateAlerts, EditMyU