Blogging Basics: Two Types of Links

This is the first post of a serie I´m writing about links.
One thing a blogger must know is how to work with links in posts. I´m not a SEO expert, but I´ll share what I´ve learned and my vision of this subject. If you think I´m wrong in any part, please correct me, that way we can learn more.
Generally speaking, there are two types of links: Do follow and No follow.
So, what´s the difference?
For Goggle, each link pointed to your blog counts as a vote. In theory, if you have more relevant/authority links pointed to your blog you´ll have better ranks. Relevant links can be from blogs/websites in your niche with good ranks, from directories with good PR, Article directories, Forums, the so wanted edu links, etc.
When your blog is crawled by Google there are two main type of instructions/tags you can give the robots regarding your blog links:

~ Do Follow links:
Means the robots will consider the link as a valid vote, they will crawl it and give that site your vote of trust and PR from your blog. This are normal links, they look like:

Ex: a href="http://name of the site">Anchor text

~ No Follow Links:
It´s a tag we add to the link that instructs robots to ignore that vote. With this type of links, PR doesn´t pass from one site/blog to another. The link works as normal but because it has the no follow tag, it´s distinguished from other links in your blog and doesn´t count as a vote. A no follow link looks like this:

Ex: a href="http://name of the site" rel="nofollow">Anchor Text