Your Twitter friend or follower had tweeted an interesting link few days back, but you are now not able to find it, then you should be trying out twitFlink. twitFlink is a simple online service which can find links tweeted by any Twitter user. All you need is to just enter the twitter username of the person you want to search and the tool lists out all the links shared by the user. Only links are tweeted and not any other tweets.
In the search result, you can also filter the list using keywords, for example if you know that the user has tweeted something on Windows 7, you can filter it using the keyword.
Although this is a very simple service, it can come handy on many occasions.