Taking a step back, you have to ask yourself is your content good enough to make people want to bookmark it? If not, sites like del.icio.us are bound to fail. Looking at the type of people as well who use these social sites, you can generally file them in a “tech-savvy” category, who will be well aware of online marketing / seo / promotion tactics. If you purposely try and befriend people with the end goal of promoting your site, you will be rumbled and ousted.

Stumbleupon is a nice simple social bookmarking tool which brings some of my sites a lot of traffic. Your social bookmarking fun will go all the further if you have “viral” content on your websites. I have experimented with many sites such as Digg, Furl, delicious, stumble and on some sites they have absolutely no effect and others they provide over 60% of my traffic.

For example, look at the tagclouds on stumbleupon – the “humor” tag is massive, so if you have a funny video website for instance, this would be perfect to promote via this method, however a blog documenting the lifecycle stages of aphids, would not be.

Coming full circle, if your content is good, then you will only need to sow the seeds.