I helped start a company called Meetrix, which delivered multi-point collaboration services back in 2001. We had a good run for about 4 years, but we ended up taking a bridge loan (bridge to nowhere), and the whole thing went through bankruptcy for $10k. At one point, the offer had been in the millions, but it "wasn't enough". Sigh.
Anyhoo, as we were strapped for cash and our original investors were all Enron guys who ended up pulling back the $5 - 10MM promised for the initial investment, I had to get creative on putting the service together. So, I looked for third-party solutions that I could customize, keeping the IP of the multipoint audio and video conferencing as our core. IBM/Lotus Sametime was the software that I selected to use as the meeting room (like now WebEx/Gotomeeting) software that would kick off the audio/video portion. In order to make this happen for our SaaS model, I had to make some *ahem* modifications to the source. What we wound up was with a "cloud" based version of Lotus Sametime that was multi-tenant. This, of course, was before anyone referred to the cloud except in fancy architecture presentations where you'd always start with a cloud representing the Internet. It was also SaaS before anyone came up with that particular popular palindrome. It worked really well, and ended up being the only thing that survived the bankruptcy and ever since, some of the guys have been working the model.
I just heard that they won the 2011 Beacon Award "IBM Cloud Computing Innovation - For Application Providers."
Meetrix is the first company to virtualize Lotus Sametime in a public or private Cloud software-as-a-service (SaaS) offering. Meetrix UC in the Cloud integrates Telco 2.0 telephony and third-party plug-ins. The innovative Cloud-based design delivers low-cost, secure, anytime, anywhere unified communications and collaboration; connecting people, data and environments and enhancing business productivity.
So there you go--Matt Roberts, Cloud Architect, for over 10 years with expertise in multi-tenant Saas n-tier web applications. I may even put it on my business card :)