There’s a blogger I like a lot, but she never links. I asked her why, and she said, “It takes too long.”

It’s true that linking does take a long time. But it’s one of my favorite parts of blogging. Sometimes I spend a couple of hours on the links – an hour reading the relevant conversations online and figuring out what to link to, and an hour arranging links in the post.

I think all the time about why I am linking, and where I should link, and what should be underneath the link. Here are the types of links that I think about:

1. The respect-gains-respect link
The Internet is very democratic about authority. Authority is up for grabs, and you get authority if you say something smart and interesting. To this end, whenever I am presenting a controversial opinion, I link to as many of my sources as possible. I want people to be able to look at the research that I am looking at and decide for themselves if my conclusion is right. Also, I have found that doing this makes conversation in the comments section more interesting.

2. Easter egg link
When my brother was guest blogging for me, every link he had was a joke. I have a background in user interface design, and at first I told him it was a bad way to link because people should know what they’re getting before they click. But then I realized that it is actually just a style of linking, and people came to expect his links to be fun. I started referring to these as Easter egg links, after the practice programmers have of adding secret messages behind the code. (For example you used to be able to type “zzzz” into a Microsoft Word document and spellchecker suggested “sex”.)

3. Here-are-my-friends links
Guy Kawasaki is the king of this. When Guy links, it is usually to one of his friends, or a friend of a friend. So Guy’s links serve to remind us of how well-connected he is. This is no small peanuts since he is, in fact, very well connected offline – especially for someone who is willing to commit to blogging regularly. Reading Guy’s blog is sometimes like the smart-man’s Page Six of Silicon Valley.

4. True-love link
Sometimes I’ll fall in love with a link and structure a whole post around it. Like this one. And sometimes I’ll save a link for a year before I use it. Usually my links are very serious – to back up some point I’m making. So I think of it as a treat for me and the reader when I throw one in just for fun. Like this one, about how to recharge and iPod using an onion and Gatorade.

5. Self-referential link
Most bloggers have pet topics they go back to time and again. So it’s helpful to a reader if the blogger links to a few of the other posts on that topic to give the current discussion context. I do this a lot, but I learned to do it from the team of writers at Techdirt. Those guys are great at linking to other stories they’ve written on the same topic. I don’t read Techdirt every day, so if I happen to be reading, I can get a history of a given topic by reading their links.

6. Hat-tip link
Sometimes, a blogger finds a very obscure piece of information, and links to it. Then, a blogger who regularly reads that blog also links to the obscure piece of information. It’s pretty clear that the second blogger got the information from the first blogger. And in this case, a nice little hat-tip is a courtesy – to say that actually, the stellar Internet research comes from someone else, not me. I do this often. For example, when I read this woman’s post because she blogged about me, and then I blogged about a link in her post. Here’s an example of someone railing against a blogger who did not follow the etiquette.

7. Link-bait link
When I first started blogging, people told me to link to bloggers who are bigger than I am. I didn’t really believe it would do anything for me, but that’s because I didn’t understand how much traffic a big blogger can send. So, I followed advice, even though I was skeptical. Here‘s the post – and it changed my life as a blogger. Literally. I linked to Lifehacker and they linked back, and for a year, that was the most popular post on my blog. Lifehacker’s audience is breathtakingly huge, and to get linked to from them is a big day for almost any blogger.

8. The friendly link
Blogging is a conversation, and it is much more fun if you are part of it, instead of just talking at people. One of the great pleasures of blogging is linking to someone who I don’t think knows that I read their blog. A link to someone is like saying, “I really like what you’re writing and in fact, I want to share it with everyone I know.” A blogger trades on ideas, so recognizing another blogger’s ideas with a link is a big deal. And it’s so easy to do, considering how nice it makes people feel. So do it.

9. The poetic link
If I write a list, and I have links to two out of three list items, I find a link to the third. I think the symmetry is important. Not like anyone will be upset if I don’t link, but I think that good rhythm to links is like good rhythm to sentences. It makes reading so much nicer. I do this in paragraphs as well – try to keep the linking structure rhythmic as the reader scrolls down the post. I don’t need to do that for meaning, I do it simply for pleasure.