Every cloud...

What does the proverb every cloud has a silver lining means?

I usually hear "every dark cloud has a silver lining" but it seems to be more popular without "dark" in Google - I guess I'm alone in assuming white fluffy clouds are good. Anyway...

Even in a negative situation there is some hope, or some good can come from something that seems bad. Similar to "It's an ill wind that blows no good."