You should use both of course, also it is going to take a lot of time to use both successful, it is worth it because you are getting to know so many interesting people.
Both are equally good, you get targetted traffic by both methods. But on same time twitter is a lot easy, while i dont like the interface of digg. It slows things up.... Twitter can fetch you more instantaneous traffic while digg will bring you constant traffic
if i have the chance to choose between the two, well i prefer digg because they are very reliable and you could be index in google in mins through digg. but i also love twitter to drive traffic to our sites.
East or west, Digg is the best... Although I am using twitter for my blog posts, digg is really out performing twitter in all aspects.
Twitter and Digg are two completely different types of website. Twitter is a social networking website (interacting with other users) Digg is a social bookmarking website (bookmarking/promoting articles and websites)
Obviously Digg wins IF you can front page your articles. One front page will get you more traffic than you could EVER get with twitter. Problem is only certain type of sites work well on digg and you need really killer content and its much harder to front page nowadays.
Digg is the best sure !! Digg is the second main traffic after google , I think twitter is very bad tool for traffic , or maybe I'm not using it in the right way !!
Both because on both sites if you have huge followers on twitter and huge friends list on digg so you can get huge traffic from both websites.