Content contributed to another publication by an outside author. Commercial link arrangements require appropriate qualification.
A guest post is an article written for a publication by someone outside its usual editorial team. It can share specialist knowledge with an audience that already cares about the subject. The contribution may include an author biography or relevant references, but a backlink is not what makes the article a guest post.
Before contributing, understand the publication’s readers, editorial process and rules for author links. A useful contribution answers a real question in that setting rather than recycling a sales page with a few introductory sentences. Expertise should be visible in the explanation, examples and supporting evidence.
Guest posting can become a link-spam concern when the arrangement primarily exists to manipulate rankings. Commercial links need appropriate qualification; paying for publication does not remove that obligation. Treat promises of keyword-rich, followed links as a reason to examine the arrangement carefully, not as proof of a worthwhile editorial opportunity.
Takeaway: Choose publications where your knowledge is genuinely useful. Agree on the topic, attribution and commercial terms before spending time on a draft.
Example
An accountant contributes a plain-English article on organizing expense records to a small-business association. The article explains a process and identifies the author’s firm. That serves a clearer reader need than an unrelated article written solely to insert a link to a bookkeeping package.
What to check
Ask whether the piece is editorial or sponsored and how any business links will be marked. Keep the article useful even if the publisher declines a promotional link. Do not assume publication guarantees leads or search visibility.
For more detail, see Google Search spam policies.