Seems like our CEO, Charlie Crystle has stirred up quite a buzz around the recent SalesForce outage (Silicon.com, CNet, ComputerWorld). You know it's made its rounds when you read it on Scoble's blog. There really is a point to be made here. I'm not necessarily convinced that SalesForce is bad just cause it has some occasional problems with it's uptime. They do need to make some improvements if they want to keep their customers though. The "outage" happened to be large enough to get the press on it, but we experience regular down times with SalesForce that hamper our sales process.
Back to the point... People and businesses are becoming more and more reliant on web services. This is great. There are a lot of benefits to them and they are mostly reliable. In my opinion, the fact that SalesForce can provide an uptime approaching 99% is incredible. But they are not perfect, and businesses relying on them without proper secondary systems in place are going to run into problems at one point or another. Take a natural disaster or large-scale power outage or even some technical problems at the local ISP level. I think there needs to be an offline option available for these times -- and if the web service provider doesn't offer them, then the customer needs to account for that in some way.
Even on a personal level, these outages can be a pain if you're not prepared. Recently the popular del.icio.us service was down for a bit. I use it on a daily basis to track my bookmarks. Not for those few days I didn't. I knew their website offers a way to store my bookmarks offline, but never took the few minutes to get them. In this case, maybe my business benefited from the outage :)
Something to consider... An approach we are taking for our software (GiftWorks) is a desktop client that works in both online and offline mode. In our case, the desktop client is fairly heavy but it doesn't have to be. The software uses online services when they are available and needed, but most of the work is done on the desktop. If the customer can't go online for any reason, they can't use our online services, but they can still do something. This is definitely not a new approach. Most email clients work the same way.