Wie sich aus § 55 Abs. 1 RStV ergibt, trifft 
  einen Anbieter somit nur dann keine Impressumspflicht, und
  er kann seine Webseite völlig anonym ins Internet stellen,
  wenn sein Angebot ausschließlich persönlichen oder
  familiären Zwecken dient.

Doesn't this say it is allowed to anonymously put a website online, if it is a purely personal/family page? I don't think she is running a business or has any commercial goals.

IANAL, but perhaps. The following paragraph actually states, that if all your content is password protected and you only give this password to personal acquaintances, then you clearly don't need an impressum. ( Along with two other examples, which also not very helpfill.)

The problem with this law is, that is says something about a page with some baby pictures ( so that grandma can see her grandchildren), and something about media corporations. However it simply does not address the case of a private blog, were the audience is not personally related to the author, but the author does also not try to make money with it.

If you publish anything that might concern anyone outside of your family you are already required to add an imprint. A complete address is required information.

A blog, a portfolio, bookmarks, dotfiles or even a simple memorial (if it's for someone outside of family) is enough.

I have not added one to anything I have ever put online nor do I intent to. I neither host in my country nor do I publish in my mother tongue. I think it is ridiculous to be forced to divulge information that allows people to knock on my door.

That it is actually illegal in some jurisdictions doesn't make it any less sad that people have to wonder about it.

There's a short description in English here: http://en.wikipedia.org/wiki/Impressum

No, it is not clear as you present it. It says that for personal use this is not required. However, what is personal is hard to say.