Technical writers deliver information to users, typically of software, that explains how to perform specific tasks. A technical content writer, however, writes about scientific and technical matters to reach a specific goal such as to explain new technology, to attract visitors to a website and other aims associated with content marketing.
These types of content writers apply a different tone and style than would be used, for example, for a user manual. It needs to speak to the target audience that is likely to be reading the content. This could be am average reader that needs scientific concepts explained in plain language or an expert reader where some technical knowledge of the subject area can be assumed. They will also consider SEO while writing their content and include relevant keywords throughout the text to make it more search engine friendly.