I think contextual linkbuilding must be made helpfull way. Linkbuilder (writer/content creator) must do it the way that he tries to help reader to get most acurate and helpfull info. So he dont links to the website main page with unrelated info, but he links to the subpage where is detailed info on the subject.. He may link to several domains, not several links to one single domain mainpage. I think its good to dont make contextual linkbuilding days or weeks after article is written, but add links immediatelly when article is published.