If I ad 20 to 30 articles to delirious, digger or any of the other social book marking sites and then ad articles gradually is that spamming?
The websites like digg.com just gets the hold of such groups, since the activities are doubtable. Its better to get original diggs, by creating topics/blog post which attract natural patterns.
I guess, you are talking about paid votes on those social bookmarking sites. I am doing social bookmarking for more than 3 months, I got offer of paid votes, I denied. To me paid votes is no a thing which should be recommended. It is something like spoiling internet.
If you do it many times and you post or ad one article to many social bookmarking i guess its spamming but if you ad article with new and unique article to a social bookmarking just like digg, it is much better. Social bookmarking gets hold a such group called social network and it will help boost traffic for your site.
Let me tell you a bit more about social bookmarking sites. We do submit a story from our site on these sites. We posts title of story and a short description. The title become anchor to the link to our site. Then, these social bookmarking sites puts our link in a queue. when visitors of these social bookmarking sites sees our link then they used to read the full story and give +ve or -ve votes. [visitor do so because our links are placed in categorized way, and the visitors who have interest in that cat used to read and vote] Now, the story which get more +ve votes.... it starts moving up and up. The story which get max votes will reach on home page of these social bookmarking sites. And then huge traffic comes to our site. So, people from all over the world can make a group using forums like DP and start giving +ve votes to each other. OR they will give +ve votes to some third person and get $$ in return. I hope now you should be clear.