You absolutely want to promote your website if you want it to generate leads or sales.
Fresh content is one of the most significant things you can do to help your site rank better. From my experience, adding about 2000 words of new content every month, spread out over numerous blog posts is highly effective at catching the attention of the spiders from the major search engines. That being said, your content should be relevant to your website and much more focused on education, helpful information, mentoring, etc. that about your business.
LInks pointing to your site are highly valuable IF they are the right kind of links. As Christopher mentioned above, links from Dribbble to his website would be highly informative and in turn relevant. In contrast, links from business directories are much less relevant and not really worth spending any time on.
So — create new, fresh, relevant, informative content regularly — and a lot of it — and your website will generate more leads/income for you.
Not necessarily, @JamesBarnsley. If you’re producing informative content that attracts developers, it can lead to sharing which in return can land you a job or produce sales depending on what your content is about.