SPWeb.PresenceEnabled property
SharePoint 2013
Gets or sets a Boolean value that specifies whether inline presence information is enabled on the website.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
The PresenceEnabled property gets or sets the raw presence value of the site, while the EffectivePresenceEnabled property returns the raw presence value combined with the global virtual server setting for presence. Use the PresenceEnabled property when creating administration tools, and use the EffectivePresenceEnabled property to display presence at run time.