TweetChannel utilizes hashtags for creating channels, or streams to watch. You must log in with your twitter username and password, no oAuth, for authentication. Begin each tweet with the hashtag, or channel name you wish to follow.
The service then basically strips the hashtag portion out to show you just the raw tweets in a timeline. Nothing fancy and every twitter client basically does this now. I don’t think you would need to make a special trip to this site that was founded in 2007/2008. It looks like they did a good early job and then let it sit.