Almost every URL that is posted on Twitter uses a short version using some online service or the other. There are also spammers on Twitter who advertise links. It's only after you click and open the link in a browser that you know what content the page holds. Tweetdeck has a feature which generates a preview of the page for you. Enable it by checking the Show preview information for short URLs option. The next time you open a link, a short 2-3 line brief of the link will be displayed and also the complete link. The number of clicks that the link has received is also shown.