First, let me tell you about what each term is all about.

Squidoo: This is a social media website wherein you can write a topic on anything that you are interested in. It may be a blog, a video clipping, music or for that matter a topic that is close to your heart. This is possible through building your lens. What is Lens? Lens is nothing but, a web page allotted to you by squidoo that can link to your blogs, photos, music links, video clippings and a lot many other things. You might be thinking what is in there for me? This is quite beneficial in many ways.

1. You can share your knowledge with others. 2. Increase your website traffic. 3. Adds to your creditability. 4. Adds to your website visibility, thereby creating a win win situation. 5. Earn income through more website traffic.

Digg: Digg is a community-based popularity social media website with an emphasis on technology and science articles, politics and entertainment. It combines social bookmarking, blogging, and syndication with a form of non-hierarchical, democratic editorial control. News, stories and websites are submitted by users, and then promoted to the front page through a user-based ranking system. Here, one can submit his own story which should be fresh in the related category. More the number of clicks (or diggs) on that story, means more popular your story becomes (means more traffic) and reaches at a higher rank in digg. Thereby, you can make it a favorite article published once you have received a good number of diggs. This differs from the hierarchical editorial system that many other news sites employ.

Article directory: This is a web directory wherein you can submit your articles, topics of your interest for sharing your knowledge with others. This is quite helpful in increasing your website traffic.

The difference between squidoo, digg and other article directories is: An article that you write and submit in an article directory is not restricted to your website alone or for that matter to only 1 article directory. It can be submitted to 100's and 1000's of other article directories for generating more website traffic, broader publicity.

But, an article that you write for a social media website like squidoo or digg reside on their site and might take a longer time to generate traffic, as compared to an article submitted in article directories.