I've been using Google's Picasa and recently its online counterpart Picasaweb for a while now and am happy with it, mainly because of the easy upload from within the application and the integrated albums listing so I know what I've uploaded.

It has permissions and licenses:

You can set an album completely private and have the system email the ones you want to give access to (they'll need a Google account to login to view it), or you can have it hidden and give the url to whoever you want, or finally you can leave it public and anyone can see it from your albums listing if they know your google username. You can also have an album private and only share specific pictures with specific people.

The licenses you set are displayed next to each photo, if you want. You can set Creative Commons licenses to dictate reuse of the photo.

The best way to try the privacy and security is to use 2 Google accounts from different browsers (say Firefox and Internet Explorer), and add and revoke rights (they call them share permissions).

Finally, you can easily upload from your N900 to Picasa (along with many others) by using an application called Pixelpipe. You'll find it on the Ovi store and it's quite flexible. It lets you upload photos to its service and based on the tags you set on the photo, route it to whichever service and album you have defined.