A startup company is a newly formed enterprise that seeks to develop and market new products and services. They may or may not have an accompanying business plan, but most startups will create one before they begin raising capital from investors. The word "startup" typically implies a company in its earliest stages of operation, as opposed to an established firm like Microsoft or Apple (which are generally referred to as "startups" only when referring to their founding).
Startup articles cover a topic from a startup perspective. These types of articles may include industry trend pieces, case studies of specific startups, or examples for how to do something within the context of a small company.