Yes, there are a number of customization options for your account.
Yes, in fact access to BlogIn internal blog is by default limited to invited members only, so it can be private to your stuff.
If you have large number of users to invite you can do so by uploading a .txt (each e-mail on a new line) or .csv (comma separated e-mails) file that contains user e-mails.
Can content on the internal blog be shared with people who do not have a BlogIn account (public link)?
Yes, administrators and post author have the option to use public link to share that particular post with anyone, even with people who don't have a BlogIn account. Anyone with the link will be able...
Collaboration on BlogIn just got a bit easier as you can now share access to any of your posts with anyone on the blog.
You can use BlogIn on your smartphone by visiting your blog URL in the web browser app, but you can also add BlogIn as a web app to your home screen for quick access.
You can upload files from your computer and insert them into posts and pages for others to view or download.