In the article it is stated:
'... EMC VmWare ESX server, both of which replace the Windows Citrix product.'
EMC VMWare ESX server is a server virtualization product, not a GUI terminal server product. It will not provide a complete substitute for the functions of Windows Citrix or Win4Lin TS on it's own.
You could load a GUI TS product on top of VMWare ESX as a virtual server.
You could also load multiple virtual systems with Project or Visio, each having a single remote connection available via the VMWare ESX remote console. This is missing much functionality, is not scalable and is a waste of an expensive ESX license.