Twitter has already signed a hearty bunch of major publishers to sign on at launch, not the least of which include the New York Times, YouTube, Huffington Post, Amazon, Bing, Digg, and eBay.
The proposed functions will work something like this. Let's say a New York Times columnist has a story posted on the NYTimes.com. The byline in the article will automatically contain a link from the columnist's name to the columnist's Twitter profile. Additionally, the people and companies (brands) that are mentioned in the article will also contain auto generated links to the Twitter profiles of those folks.
Upon hovering over the link, a small "info card" will come up showing you some details about the individual or brand's profile. From there, you can easily choose to follow the person.
The idea is to allow you to discover more Twitter profiles and interact with them without the need to leave the publisher's website.
Historically, looking up a writer or blogger's Twitter page was somewhat of a manual process. You would have to search for that person's twitter account, verify it is actually them, and then follow them.
This will serve to limit the amount of work required by each user to interact with these Twitter users.
As for Twitter's potential growth, this will expose hundreds of thousands of Twitter profiles to the unsuspecting masses. You might not know that your elected official has a Twitter account, or that a certain celebrity is a regular Tweeter.
The coming @anywhere system will streamline the discovery of new Twitter content for current and non-Twitter users.