What's wrong with that?
Yes, there is a very concerning growth of supressing individual freedom in (Western) Europe but there is also a fully grown up new generation who can't differ between freedom of thought/expression and an insult.
They think they can spit around under the free speech excuses.
This Californian decision however promote freedom in a way of supporting rights of any "intermediary" such as an ISP, to transmit opinions/toughts and even insults, without immediately being liable for the information presented.
It is nice to see some common sense in this sombre time.
However, note that a website, forum, an individual or other internet entity does not have full immunity (rightly) from the common law, contrary to some opinions here and the original Msnbc's conclusion.
I think she (Mrs. Rosenthal) was obliged to remove the defamatory content if asked to do so.
Instead, SHE was sued for defamation.
Anyway, we still only need a fair and unbiased interpretation of the common law(s). Long way to go.