I often get involved in conversations about which channels are best when it comes to sharing content - is Facebook better than Twitter? What about newsletters? How about LinkedIn Groups? 

Well the good news is that it does not matter.  The important thing is who is saying it and do you know them.

If the reader knows you and if they trust you then it is far more likely that your content will be read by them and shared by them.  So use the channel that they are on.

Both this post by our client Kingpin - it's Not B2B. It's Not B2C. It's H2H... (as in Human to Human) and in the quote below the importance of relationships between people are the key.   i could not agree more.  Do not write for the 100,000 people you'd love to read your post but rather write for 50 who are likely to actually read it because they know you and trust you and they are the most likely to share it.