I use Openfire and SparkWeb everyday and recently starting evaluating Clearspace to power the community I am building for my wife's education consultancy (www.inspiredfutures.co.uk). As I had limited computing power and memory to work with on my hosted server, it became expedient that I needed to integrate all three products under the same web server and Java JVM.
The first thing I did was to make an openfire plugin out of Clearspace
The next thing I did was to enable SparkWeb display an HTML page from its chat container
The result is what you see above and I am very pleased with it (chuffed as we say in the UK). The benefits of integrating Openfire and Clearspace has already been mentioned here . Adding SparkWeb to that combination in order to have realtime messaging, desktop sharing, Red5 audio/video calling and a SIP phone makes a compelling case for me to use Clearspace
I have reservations about real-time integration with web applications that use the MVC model based on Stuts like Clearspace or even PHP applications like SugarCRM. Even Salesforce.com also falls into the same group because they all build their UI on the server and everytime the user does anything that requires a server fetch, the screen goes all blank while you wait for the whole page to be rebuilt from server-side Java code.
Putting a softphone or an IM client as a widget in these applications requires constant connect/disconnect cycles as the user moves from page to page. It reminds me of my attempt to build a real-time application on an Apple iPhone and a softphone in Salesforce.com. What we need is to be able to keep our widgets UI resident on the client as well as the user session in the plugin on the server. I am curious to see how Jive Software implements the realtime widgets in Clearspace.
If you want to use SparkWeb as a container for your web applications as I have done, pick up the latest version of the Red5 plugin from here. Copy and edit index.html. Change the httpLabel and httpURL parameters to your preference.