OpenID is great idea, but adds another layer of complexity for early adopters. This might not go down well with the startups who can end up loosing important initial users. Also bigger companies like Google will offer Single Sign-on only for their own apps which becomes another point of disconnect. In my case I use Writely for document editing, Editgrid for spreadsheet, and del.icio.us for bookmarks which is a pain to manage.
As for offline usage, that is a very much required feature. Especially Writely should be able to implement that part easily since they have already cracked the algorithm for multi-user data edit and sync. Groove networks does offer that feature but is not for individual.
I guess there is some miscommunication in what OpenID is and how it actually lowers the barrier to entry to try new Office 2.0 applications.
This is how I see it.
I have my blog URL that is openID enabled or I have an i-name. I now can go to any one of the new groovy Office 2.0 applications and instead of getting yet another login and password. I just use my OpenID. I don’t have to put it into that spreadsheet of all my names and passwords or just use the same one I use everywhere that is totally insecure. Instead I bring my identity to the site. I save time. If I am an early adopter type I will likely get an OpenID relatively quickly and it will be a handy fast way for me to try these things out. Of course Office 2.0 applications should not force people to have OpenID’s those who want yet another user name and password can have one.
I know personally I avoide signing up for anything new that requires yet another login. I would be more inclined to tryout an Office 2.0 application that has OpenID as a login option.
I think all these office 2.0 copmanies can collectively compete with the big silo’s by offering SSO amongst themselves.