Yes social bookmarking is very useful for fast website indexing and from that you can get back links.
Yes this is quite effective and if you have blog on which you post on regular basis than simply adding every new post to the top 20 social bookmarking is always helpful. You will see the improvement in traffic. More and more people will come to know about your website. So simply go for the top 20 social bookmarking and believe me this is quite effective.
Really - it depends on what subject it is. If your website is about "losing weight" - Social BM sites can help - but if it about let's say business - you won't have any luck
Obviously, social bookmarking is the best way of getting free backlinks and effective search engine indexing. Digg, reddit, stumbleupon etc are the best social bookmarking sites
Search engines view social bookmarking as a way of determining what people find important or interesting. Google ranks these sites very highly due to this.
Hello Julia, This is a successful method I have personally used and have had great results. It is called building a linkwheel. Basically, a linkwheel is a set of SIX Web 2.0 properties interlinked in a “wheel†structure, all promoting a page on the web which is the focus of that particular “wheelâ€. google "the Lemonarian" and he explains it very well. Hope this helps John Turner