That headline sounds like the setup of a joke.. "Ok, ok, stop me if you've heard this. Three Citrix marketing folks go into a bar and get completely wasted..."
Seriously, the article I wrote Friday about the subtlety of Citrix's client name changes seemed to create more confusion than it solved about all the names and versions of the various Citrix ICA clients. I spent some time digging today and I think I've sorted out all the different names, packages, and versions of the Citrix ICA client software. (Unfortunately I haven't sorted out the "why" yet.)
The ICA Client
This is the original name of the client software that seemed to work fine for ten years. If we were scientists, this would be our 'control.' Historically there were Program Neighborhood, Program Neighborhood Agent, and Web packages available. You could use any of the three packages to connect to seamless published apps or to full desktops.
The XenApp Plugin
This is the new (current) name for the ICA client. Like the previous versions, there's a regular package and a web package, as well as EXE and MSI editions available. The main question with this client is "plug-in to what?" The XenApp Plugin MSI is a standalong package that you just install. The end. As far as I can tell, this is just the new name for Version 11 of the normal ICA client. I'm not really sure what it "plugs in" to.
This is the new client framework that Citrix announced / released at Synergy 09 a few weeks ago. The Receiver is a centrally-managed client framework that can accept plug-ins for things like ICA, SSL-VPNs, passwork management, WAN acceleration, etc. The Receiver itself doesn't actually do anything except provide a way for admins to centrally configure, manage, and update all the various pieces that need to be installed on a client device. The "server" component that goes along with the Receiver to manage it on the back-end is the Citrix Merchandising Server.
Online App Plugin
Supposedly this is an actual "plug in" for the Citrix Receiver that gives it access to online apps via the ICA protocol. The current version is 11.1.1. However, there's text that says "Use of the Online app plug-in 11.1.1 independent of Citrix Receiver is not supported," which suggests that use of the online app plug-in 11.1.1. independent of the Citrix receiver is actually possible. And from what I can tell, the 11.1.1 beta client is in fact a "normal" ICA client.
My guess is that Citrix's decision to only support the 11.1.1 client as an actual "plug in" to the Citrix Receiver is temporary, and eventually there will only be a single ICA client that can be used on its own or plugged into a Receiver. (After all, Citrix has to have some support for people to connect to apps without forcing them to build a Merchandising Server.)
This is that iTunes-looking add-on to the Citrix Receiver that makes finding and running applications fun! (sarcasm). Think of it almost like a "skin" for the Receiver. You'll control Dazzle with the Merchandising Server along with the Receiver.
Do not confuse this "Desktop Receiver" with the "Citrix Receiver" because they're in no way related. The "Desktop Receiver" is a fancy name for the normal ICA client software that has a special look-and-feel geared towards connecting to remote desktops instead of single published seamless applications. Citrix intends for this to be used with XenDesktop full desktop sessions, although really there's nothing stopping you from using the Desktop Receiver client with Terminal Server-based XenApp published desktops.
So why bother creating a dedicated ICA client for full desktops when the normal ICA client has worked fine for years? The main reason is because if you run a remote desktop session full screen, you end up hiding your local start menu and desktop and stuff, and it can be kind of confusing to users. So Citrix took a hint from Microsoft and added that pull-down pin menu thing to the top of the screen to make it easier to switch between the full-screen remote desktop and a local desktop.
You can use the Desktop Receiver to connect to multiple simultaneous remote desktops, and if you have to windowize them, there are some cool new pan and scale controls that pop up to make navigation easier.
Desktop Receiver Embedded Edition
Raise your hand if thought the "embedded edition" of the Desktop Receiver client was for use with XP Embedded clients. Now slap yourself with your raised hand, because you're wrong. The Embedded Edition of the Desktop Receiver is for users or clients who will ONLY use full screen remote desktops in situations where they will never interact with the local desktop or local applications. (In a sense, it's used when you want to convert a fat PC into a thin client, err, "desktop appliance.")
So really the full version of the Desktop Receiver and the Embedded version of the Desktop Receiver are about 99% identical, but the embedded version only supports full-screen mode for the remote desktop connections, it only supports one single remote session, and it doesn't have the cool toolbars for switching between local and remote desktops. (The embedded desktop receiver is still a Windows app though. So you still need a DOMAIN-JOINED Windows OS on the client.)
You can also configure the Embedded Desktop Receiver with the address of the Desktop Broker, so the user can login and get their desktop immediately without having to use Web Interface or anything.
The concept of having two different full desktop clients--one that is remote desktop only and one that also allows interaction with local apps--is fairly brilliant and handled in an elegant way by Citrix. The only stupid thing they did was in the naming. (Again, the "HEY LET'S GIVE ALL OUR PRODUCTS THE SAME NAME problem they've had in the past.)
So there you have it. One protocol. One client platform (Windows). Seven client choices. Good luck!