Include external links
I should send people to other sites? Yes, you should. External links are the cornerstone of the web. When you first start blogging, you're most concerned about links that direct people to your site (backlinks). They're important, but they're not all there is. Linking to other sites from yours is important too!
Adding links adds value
Whether internal or external, hyperlinks make your articles more substantial by giving readers the ability to go further and learn more.
To link and be linked to: a virtuous circle
Bloggers monitor their backlinks! Linking to another site means the owner of that site will notice you. Once you've linked to another's site, that person will be more likely to link to yours, especially if you write about the same subjects. It boils down to the philosophy that if you give something, you'll get something in return, and if you do something, others are more likely to return the favor.
Don't worry about losing readers
It's unrealistic to think you can keep a reader on your site by not including external links in your articles. You're better off making sure readers want to stay by offering them good content that is exclusive, original, illustrated... Basically that means QUALITY content!
Put links at the end of paragraphs
Reading on a screen has its own set of issues. When readers encounter the different formatting of a hyperlink (colored, underlined, etc.) it can be disconcerting. They can lose their place, and it might make them stop reading your article. Try to put your links at the ends of paragraphs, on words that accurately reflect the information they'll find.
Another thing: Google adores links too. So link away!