Over the last few years, I ended up with multiple domains all registered with Google Apps. One of the things that I was amused with Google Apps was their ability to allow me to sign-in simultaneously to more than one account. I could sign in to the regular gmail account and one or more of my domain related mail accounts hosted by Google Apps. But something happened a few months back and now I can only sign-in to one account at a time. I don’t know what prompted them to take away this feature. Around the time this started, they also used to show some intermediate page about business account vs personal account and I don’t really understand what they are trying to say, sort of. It probably could have been presented much better.
If you are a web developer, you would know that typically cookies are used to support session and typically one flow is supported per session. There are very few RIA frameworks that can support multiple flows in the same session. They do this by using different flowids and then tracking the backend model at the flow level rather than session level. Infact, J2EE specification only has 4 scopes : request, page, session and application. Flow scope is not something easy to implement and only a few frameworks support them.
So, obviously I was quite excited by the fact that Google supported the ability to login to multiple Google Apps accounts at the same time all accessed via their domain. But that’s gone now and don’t know if it would ever come back.