If you made use of the Autodesk® Seek, you should know that as of January 16*, 2017, that service has been transferred to BIMobject® Cloud Solution. Links to Autodesk Seek will be redirected to BIMObject. Read more about the transfer in this Autodesk Knowledge Network article. Read more about BIMobject Cloud solution at the BIMobject website.
* - or, perhaps January 18, depending upon whether the date in the AKN article or redirect dialog is correct.