For example, look at this article: http://www.wired.com/epicenter/2011/01/twitter-let-the-tweets-flow/
Then click on the link at the top of the 3rd paragraph that says "#jan25 movement". You should not be able to return to the Wired article unless you click the back button a few times repeatedly. Otherwise, you will alternate between the url's https://twitter.com/#, https://twitter.com/search/%2523jan25#, and https://twitter.com/search/%2523jan25#search?q=%2523jan25. This seems to always be the case when an article links to a Twitter page without opening a new window/tab.
As this is obviously quite frustrating, I was wondering why they have chosen to do it. It'd also be great to hear a technical answer on how they do it if it's not too complicated.