Sharing valuable content can grow your expertise and influence online. Lots of up-and-coming entrepreneurs want to create organic and cost-effective buzz about their products and services but aren’t sure how to get started without hiring a PR agency. Whether you have a PR staff or not, there are still several influential online outlets for sharing high-quality content and valuable information that will help you spread your influence.

Here are three great sites you can write for that will help you expand your influence -- and they’re all free.

1. MediumStarted in 2012 by Twitter co-founders Evan Williams and Biz Stone, Medium is a collaborative writing space to share your writing. The user interface is simple and easy to navigate and you can call on other writers for help with editing, ideas and more. It’s a highly social place such as Tumblr or Blogger (another of Williams’ projects) that’s designed to cater to writers and readers the way Tumblr caters to socially sharing images. The site even tells you in the article how long it should take you to read. You can create a free profile and join this prolific, highly social and inviting community to meet cool people and write great content.

Related: How to Become an Expert in an Hour

2. SlideshareSlideshare is a great resource for information as well as to create original content to share. The content on slideshare tends to focus on presentations, giving you the maximum information in the most condensed format. As the site has grown, the content has evolved. You can now find incredible infographics, common documents and videos. The site is free and increases your likelihood of having your content go viral as this voracious community is constantly sharing and promoting.

3. QuoraThis question-and-answer-based platform has grown exponentially over the years and seeks to be the information hub of the internet. Think of it like a social Wikipedia. Ask any question you can imagine and get answers from any manner of experts and casual bystanders. The most popular questions rank highest on the site for the best exposure, so make sure your query is a broad-reaching topic you’re truly interested in. Better yet, build your own expertise and qualifications by answering open questions. Responses are voted on by other Quora members and the better your answer, the higher it will rank. It’s a simple concept that can be a fascinating experience as both the asker and answerer.

Related: Want to Be an Entrepreneurial Icon? Try These 5 Steps.