The collaboration space for this group is being developed outside of my.usgs.gov, in Sharepoint. To access this site, follow the link below and use your AD login (that is, the user-id and password you use to log into your computer). Note that you use your Lotus user-id and internet password for my.usgs.gov.
Link to Sharepoint collaboration site for ArcGIS Server on the Cloud: https://xcollaboration.usgs.gov/wg/wim/birdsofafeather/SitePages/Home.aspx
This group is a bit dormant at the moment.
If you are interested in ArcGIS Server on the Cloud, you can head over to the Geographic Information Systems Community of Practice page.