If I go to the twitter page of someone I'm following, and click one some of their tweets, on the right column I can see responses. However, when I click on some of their tweets, I don't see responses, I just see other tweets that they made and how many people retweeted that tweet. Does that mean that there were no responses to these tweets?
Yes, it could either be that particular tweet is not part of a conversation (i.e No one replied to it or the tweet itself isn't a reply) or it maybe part of a conversation but the other person has protected their tweets.
Protecting your Tweets
To protect your tweets Log in to Twitter and navigate to your Settings. Then scroll down and tick the check box
Protect my tweets
Save to confirm your changes.
How does someone protect their tweets? Mar 19, 2011 at 20:18
@z-buffer - I have updated my answer. Thanks Mar 20, 2011 at 9:46
What if you respond to someone's tweet with a protected tweet, and they retweet your tweet? What if others respond to a protected tweet, are those also hidden from a search? Mar 20, 2011 at 18:27
1@z-buffer - A protected tweet cannot be retweeted. If you respond to a protected tweet then the unprotected tweets are visible to everyone. The protected tweets will not be visible unless you have been approved to view them. Mar 20, 2011 at 18:40
So a response to a protected tweet will be visible? Mar 20, 2011 at 18:45