Guest posting is the practice of writing and publishing an article on someone else's blog or website, and it's a great way to promote your website and build your brand.

When you write for another website, you give them extra content their readers will enjoy, which can help increase their website traffic and improve their online presence.

Here are some benefits of guest posting:

• Gain fresh audiences
  Guest posting on a popular blog or website can expose you and your brand to a new audience. This can help you reach potential customers or readers who may not have found your website otherwise.
• Build your authority
  When you write a guest post, you can showcase your expertise in your field. This can help you establish yourself as an authority in your niche and gain credibility. This credibility will generate respect and positive engagement from readers and fellow bloggers alike.
• Generate leads
  Writing for other websites can help you generate leads for your business. When you write helpful and informative articles, you can encourage readers to visit your website and learn more about what you have to offer. And this creates the more tangible benefit of more leads and sales for your business.
• Improve search engine rankings
  Most blogs allow you to include a link to your website in your author profile, bio, or sometimes within the article. Backlinks are a highly significant factor in SEO and can help improve your website's search engine rankings – providing it's not overdone, and the websites you post to are of sufficient quality.
• See more visitor traffic to your website
  By virtue of a link to your website, or readers searching for you online, you should see some increase in traffic to your website and a positive effect on your search engine ranking.
• Networking
  Guest posting also allows you to network with other bloggers and website owners in your niche. This can lead to new opportunities, collaborations, and partnerships.
• Learn from other bloggers
  When you read other people’s articles, you learn a lot about their writing style, content marketing strategy, and other aspects of blogging. This can help you to improve your own blog and attract more readers.
• Get higher social media exposure
  Most serious blogs and websites promote their content on social media. When you write for their site, your content will inevitably be indirectly promoted to their social media audience, giving you additional exposure.
• Create a base for constant improvement
  Always be looking out for ways to do better! 
  Analyze what people do when on your website, read (and respond to) feedback, and never treat what you have done as set in stone. You are working for your readers (and those of the websites you write for), so make sure you adapt and get better at satisfying their needs.

If you're looking for a way to promote your website, build your brand, and learn from other bloggers, then guest posting is a great option. Just be sure to keep to their publishing rules (they are often published on a “Write for Us” page, and here’s an example of the kind of quality guidelines you will need to follow). And if you write high-quality content that is relevant to your target audience, and you’ll have a great resource that works continuously to your advantage.