I've been watching the web-based desktop applications as news has come out about them. At some point I expect they will get to a level of maturity that companies will start making a big leap, replacing MS Office on their employees desktops with access to one of these. It makes great sense - the employees no longer need powerful pc's, their pc's no longer have to be backed up (as the documents will reside on the server), employees can access and update their documents using any pc anywhere where there's Internet access, and there's a much reduced need to do desktop updates.
In addition, the combination of these apps and SAAS (having these hosted externally and paid for as a subscription, rather than licensed and installed internally) will become more enticing. However, the developers of these apps will have to assure organizations that their service is virtually 100% reliable and the data is secure.
I haven't seen an app that's ready to replace MS Office, but I remain hopeful.
These apps look like good integrations of open source apps in virtual desktop interfaces, and I'll watch to hear more about them.