Hypertext is one of the underlying concepts that defines the structure of the World Wide Web. It is the main reason the Web is easy to use and can share information in a flexible format. Hypetext is defined as "text displayed on a computer or other electronic device with references (hyperlinks) to other text that the reader can immediately access, usually by a mouse click or keypress sequence. Apart from running text, hypertext may contain tables, images and other presentational devices. See Wikipedia.
You are using hypertext as you read this Blog post. All of the Bloggers are using a modified form of hypertext to write their posts and link to other websites. If you are using Blogger as your blog host, then you will always see a selection for Edit HTML as a choice when editing your posts. Clicking on that selection, puts your post into a modified form of HTML that can be edited directly in the Blogger editing box. Obviously, it is not necessary to learn HTML to write a blog. But learning a little bit about HTML and thereby learning about hypertext is a useful tool to extend the capabilities of your blog posts.
Wikitext language or wiki markup is "a lightweight markup language used to write pages in wiki websites, such as Wikipedia, and is a simplified alternative/intermediate to HTML. Its ultimate purpose is to be converted by wiki software into HTML, which in turn is served to web browsers." See Wikipedia. Since the FamilySearch Research Wiki is a derivative of MediaWiki, nearly all of the commands and features of wikis such as Wikipedia, are implemented in the Research Wiki. If you would like to see a selection of the wikitext implemented in the Research Wiki, click here. In addition, many HTML tags can be used in wikitext.
Don't worry, if you never learn anything about wikitext or HTML other than the most simple commands contained in the Blogger editor or in the Rich Text Editor on the Research Wiki, you can still add information to the Research Wiki. But if you have a desire to get deeper into the programming aspects of both blogging and contributing to the Research Wiki, you can follow all the links from the pages I have cited above.