Linking to other articles you've written on the same subject just makes common sense if you know your readers are interested in the subject matter. This does not mean linking to everything you've ever published on the subject on NowPublic or elsewhere, but directing your readers to the right page is like holding the door open for someone who's going down the same hall you are, it's just courteous.
Creating "content hubs" can be one of the best ways to increase your traffic. Think of articles like spokes in an umbrella that all connect in an arc to embrace what's beneath it. These hubs tell spiders and readers that you've got a hefty amount of information on every aspect of the subject and you're not afraid to share it.
When you are thinking about what words will become the link, ie the anchor text that the reader will click, be judicious. Don't go crazy - 1-3 words at most. Use nouns that describe what a reader will find there and verbs for what they'll do there. Vary the terms of your anchor text. Creating heaps of links with identical anchor text will quickly be detected as a link-building effort (i.e. not natural) and spiders hate it when you do this.
If your link-to-text ratio is off the charts, the page will be cluttered and will distract readers from the real content and the most valuable links. If you have a 600-word article, 5 links is plenty. It would be nice if you linked on NowPublic (internal) if we had relevant content to make the site "sticky," but there are one or two sites out there (external) that offer more than we can so link to the best and hopefully they'll return the favour some day.
To create a link to another page or an email address, highlight the text that will be underlined, ie your anchor text, and click on the globe-and-chain icon in your text editor toolbar above the body window. A new window will open allowing you to choose the link type, either the url or email format, from the drop-down menu. Next fill in the www address for the url or the email address with an @.