What does a min check raise mean?

[rwanger]

I was min checkraised last night, and then the guy immediately went all in on the turn ~$120 into ~$150 pot. Am I correct in thinking that the min checkraise usually means a very strong hand? A min raise is a totally different animal, but with the checkraise they have to lead out into you on the next street.

I'd like to know what everyone thinks, based on past experiences.