This thread is heading way off topic, so this will be my final reply.
The short answer is yes, adding a link to just about any social bookmarking site must be done manually.
All Sociable does is give you icons that, if a user clicks on one, will take them to the appropriate social bookmarking Web site and fill in the appropriate form for the user. It is up to the user to then submit the form.
There is no practical way to "automatically" submit your posts to most social bookmarking sites.
All the good social bookmarking sites have anti-robot measures, such as CAPTCHA, to prevent bookmark spamming. And yes, automatically creating social bookmarks of your own posts is spamming.
You might be able to develop code that allows you to automatically add social bookmarks to your own accounts on the various bookmarking sites. However, it sounds like you have already encountered the problems such a program would face: It's going to be unreliable and it's going to be expensive to create / maintain. About the time your developer figures out how to defeat a site's anti-robot measures, they will figure out a new way to block your robot.
The idea behind social bookmarking is simple: I look at something on the Web that I did not create. I decide it is interesting. I add it to Digg or a similar site, or I rate it at Yahoo! Buzz or a similar site.
My friends on the bookmarking site see that I liked that content. They look at it. Then they bookmark or rate it.
The process is repeated. Therefore, the Web as a whole rates good content.
All Sociable does is make it easier for people to bookmark your posts if they like them. A system that takes away the independent nature of social bookmarking certainly defeats the intent of social bookmarking, if not the purpose.