What is a Webmaster?
A webmaster is someone who manages a website, typically its owner or a developer hired to manage it. If there is a problem with a website, a visitor might be able to contact its webmaster to inform them of it. Articles to improve websites have webmasters as target audience.
The term webmaster is typically used in reference to small scale websites managed by a single person, such as a blog, informative portal, or institutional website. An extremely large website (or "platform"), e.g. Wikipedia, wouldn't have "a webmaster." It would have a team of web developers, of content writers and editors, and staff to handle inquiries from visitors.