Excerpt from the article by Search Engine Watch:
"Evergreen content is a valuable resource for your website. The term "evergreen content" refers to content that won't quickly become out of date or totally incorrect within a short time period, such as a week or a month. You add updates as needed, linking back to it from new related content, and socialize with each change or whenever the topic again becomes timely.
Let's look at 12 types of evergreen content (here just is the list):
1. Yearly Posts That Can be Updated;
2. Posts That Track Something;
3. Interviews;
4. How-to Posts;
5. Posts About the History of Something;
6. About Us Pages;
7. User Tips;
8. Testimonials;
9. Reviews;
10. Curation Posts;
11. Personal Biographies;
12. Resources.
So when you're struggling to figure out what to write about, consider something evergreen. No one is going to churn out 100 evergreen posts a week, nor should they, but it's good to recognize the power of content that isn't outdated within a few days. People like it. They like sharing it, and that increases the odds that you'll attract links."
Each tip is analyzed with more information and example. Read full original article:
http://searchenginewatch.com/article/2333083/12-Types-of-Evergreen-Content-That-Attract-Valuable-Links
Via Giuseppe Mauriello
This is a great overview article with examples of good evergreen content. I found it very helpful!