Here are some notes on how to use twitter for a large publishing site.
Twitter is a tool. Use it how you like. If someone doesn't lke what you do they can unfollow you. Different techniques will work for different sites and different goals. This lot should work for publishers.
Use tweetdeck. Set up a group for newsfeeds from relevant sources. If you see a great story, tweet the source.
Perhaps twitter's most powerful tool is the retweet. Only with retweets will your tweets go viral.
Make sure you retweet others. Not only does it make you more likley to get retweets - it creates a community. It's like people talking in a village or at a party. You're saying "heh, did you hear what Joe said about the Nicks?"
Find people with your interests and follow them. After a week, unfollow those who do not follow back. Try twitter karma for this.
As well as having fun, spreading your love and knowledge, you are building a list and this will not happen overnight. be patient and persistent.
How will searchers find you? List your publication's subjects and you will be found by people you want to talk to.
If your publications talk to the world then so should you. Don't restrict what you tweet about to your own country. So if you're an English language sports site, write about sports in the US, UK, Australia, New Zealand and Ice Hockey (that's Canada), etc.