News of what God did (Exodus 18-20)

I am curious where Jethro heard of what God had done with the Israelites, as is stated in Exodus 18:1).  For me, it's really easy to lose sight of the fact that there were other peoples living in the area, and it is probable that news of what was going on in Egypt had spread to other areas of the region.  It might be easy to under-emphasize this point, but I think it is worth considering because it indicates the enormity of what the Lord did for Israel.  He didn't merely lead them out of slavery: He did it in such a way that people from miles around would know that He was God.  How long has it been since "news of God" has traveled around the world?  Has God's work in our church been so significant as to warrant discussions from other people?  Should that even be the case?  It seems here that when God worked miraculously people heard about it.