Yes, there are plenty of desktop apps and mobile applications that let you use Twitter outside the Twitter.com website but what’s coming in the next version of Twitter is even more exciting.
You will be able to follow new people and even tweet about interesting links without leaving that web page.
Imagine being able to follow a New York Times journalist directly from her byline, tweet about a video without leaving YouTube, and discover new Twitter accounts while visiting the Yahoo! home page—and that’s just the beginning. Twitter has proven to be compelling in a variety of ways. With @anywhere, web site owners and operators will be able to offer visitors more value with less heavy lifting. link.
Initially, this feature will be available on sites like Amazon, AdAge, Bing, Citysearch, Digg, eBay, The Huffington Post, Meebo, MSNBC.com, The New York Times, Salesforce.com, Yahoo!, and YouTube.