Should minor links be styled with the same hover effects as primary links?

1. Should all links be underlined?
2. Should hyperlinks always be blue?
3. What are the best hyperlink colors code?
4. Should hyperlinks be bolded?

Should all links be underlined?

Assuming the link text is colored, it's not always absolutely necessary to underline it. There are two main cases in which you can safely eliminate underlines: navigation menus and other lists of links. However, this is true only when the page design clearly indicates the area's function.

Should hyperlinks always be blue?

Some shade of blue is good, not necessary the default one. For desktop clients, adding underline on hover is nice and makes the color less important, but for mobile clients you need to convey that the link is clickable without any user interaction before.

What are the best hyperlink colors code?

According to a study in link readability, the regular Web user sees blue-and-underlined text as links. Blue and underlined is a good standard to stick to, for no other reason than it's what we Internet users have been acclimatized ourselves to.

Should hyperlinks be bolded?

Using bold on links is neither correct nor incorrect; however in terms of UX (User Experience) users should be able to distinguish what a link is and is not.