More and more publishers are offering free digital access to archived contents. Some, like the New York Times, have designated a persistent link and provide this PermaLink as a tool on the article's page. Even if a permalink tool is not provided, you can often get the persistent link by using other Share tools for linking in social software like MySpace or you can Email the article information and link.
The New York Times offers some SHARE tools. Clicking on PERMALINK will cause a window to pop up with a persistent link to the article.