A PR Distribution Channel, or project posting feed, is a showcase of project news and activtiy that have something in common, like "Projects by Austin Designers", or "2018 Homes by HBA Members". The feed/gallery is usually embedded in a website that has other content related to the theme. By posting your "PR News" into these feeds you can increase brand exposure, direct qualified traffic and increase the Search Engine Ranking of your website.
It is the public webpage that is the full project profile, or project case study. It can reside on:

Your website (example http://www.your-website.com/projects/name)
Project Presenter (example http://www.projectpresenter.com/company-name/project-name)
or a completely separate website (example https://en.wikipedia.org/wiki/M1128_Mobile_Gun_System).

When you post a PR News, you are often including a link to 'Read more about this project' that directs people to your Project Landing Page.
To save time and money, companies often use Project Presenter as their company's living archive of past and current projects. Their legacy. From this single repository they can store data that only their company can see while controlling what the outer world sees, and where they see it.

You can deliver both a full project portfolio into your site, and/or your PR News.

To manage project showcase content on your own website you can connect to any existing or new website to Project Presenter by three ways. Widgets galleries which can drop in code and pull project content directly from your archive. Another option for full speed and design control is API (Application Programming Interface). Lastly if your site is a WordPress site, you can use the ease and speed of our WordPress Plugin.
Your first 3 postings will stay until you unpost them, or if the PR Distribution Channel manager decides to unpost it due to it being too old. If you have many postings they will stay posted live driving up your Search Engine Ranking until you decided to downgrade.
@Mentions are the listing of 'other contributors' to a project often listed below or next to a project profile containing the company's name and their role on the project.
Everyone has complete control over their own project profile, or 'public view' of a project. Even though there may be many contributors associated with the project internally in the system, you choose what contributors you want displayed in your public view of the project.
Absolutely, and you should. PR News are meant to be small news 'blurbs' about a project. The Designer will likely show different pictures and describe the project in a completely different way as the Engineer. Plus, displaying each other in the respective @Mentions only helps one another.