Most "experts" answering to the negative on this question usually resort to reciting the Google tos about creating links to manipulate search engine rankings. The whole field of SEO is about manipulating search engine rankings. So, I think that saying a self-created link from a Web 2.0 site to your "money site" is something nefarious or black-hat is a joke.
There should be nothing at all detrimental about creating a blog on, say, Weebly, having a high-value piece of content linking back to a self-hosted company website. It is not like you are using automatic software to create 100s of crap articles.
So how are you supposed to get backlinks to a company website to boost its search rankings? All the prim and proper answer I have ever gotten for this question is "write good content and they will come". Fine. But I don't have 17 years for my site to grow and attract attention.
I understand that things that have worked in the past won't necessarily work in the future. But, I just can't see why a great piece of content will be worthless on a free-hosted Web 2.0 site. Everyone talks about "Content and Backlinks", but every source of backlinks I have ever used have been labeled as bad and worthless. Commenting? Bad. Forum profile? Bad. Web 2.0? Bad. Article Directories? Bad. Guest posts? Bad.