Is it better for readability for links where link text equals document title to both be in title case, or both be in the usual capitalization?

1. Is title case or sentence case easier to read?
2. Why do people use title case?
3. What is the difference between sentence case and title case?

Is title case or sentence case easier to read?

Sentence Case

It's considered the most readable form of text.

Why do people use title case?

Some people think title case looks better because it's more symmetrical. As long as your phrases are short, title case creates a nice visual rhythm to your words: There's beauty in symmetry, and sometimes that's a good enough reason for a designer or writer to choose title case over sentence case.

What is the difference between sentence case and title case?

In title case, major words are capitalized, and most minor words are lowercase. In sentence case, most major and minor words are lowercase (proper nouns are an exception in that they are always capitalized).