Bettween is a new conversation tracker for Twitter. Hailing itself as the ultimate in its class, Bettween allows you to input the user name of two twitter users and follow any conversations between them. It’s a good way to follow unfolding conversations between celebrities, or keep track of previous conversations you’ve had with your followers.
We’ll warn you now, if the people you search for tweet a lot, it could be up to 5 minutes before any matches are displayed. It does attempt to go back as far in tweets as possible, but this is apparently only done once so the lag will not show again. Also, no authentication is required, so this means if they have protected tweets you will not be able to capture the data.