Of all the accessibility enhancements that can be made to a page, adding a "skip to content" link is one of the easier wins. These links allow keyboard-only (non-mouse) users to quickly jump to the page's main content or other important sections.
In fact, if you need to conform to WCAG, Level A or above section 2.4.1 requires it.
"A mechanism [...] to bypass blocks of content that are repeated on multiple Web pages."
There's some important nuances to this seemingly simple feature, both in use and implementation, that I'm going to explore.