Once Google rolled out Panda algorithm, it hurt a lot of websites. Some of my friends' websites dropped from page 1 to page 50, some of their websites actually improved in ranking. Each time Google rolls out new algorithms, a lot of websites will be affected. And Google tells on Google Webmaster Central Blog, Panda was just one of roughly 500 search improvements we expect to roll out to search this year. So what you can do to make sure that each time when Google rolls out new algorithms, your website will not get affected or munimum?

Luckily, Google tells us what they want. In Google Webmaster Central Blog, Amit Singhal (a software engineer at Google Inc.) shows us a guide on building high-quality websites. The guide contains 23 questions which we have to answer.

1. Would you trust the information presented in this article?
2. Is this article written by an expert or enthusiast who knows the topic well, or is it more shallow in nature?
3. Does the site have duplicate, overlapping, or redundant articles on the same or similar topics with slightly different keyword variations?
4. Would you be comfortable giving your credit card information to this site?
5. Does this article have spelling, stylistic, or factual errors?
6. Are the topics driven by genuine interests of readers of the site, or does the site generate content by attempting to guess what might rank well in search engines?
7. Does the article provide original content or information, original reporting, original research, or original analysis?
8. Does the page provide substantial value when compared to other pages in search results?
9. How much quality control is done on content?
10. Does the article describe both sides of a story?
11. Is the site a recognized authority on its topic?
12. Is the content mass-produced by or outsourced to a large number of creators, or spread across a large network of sites, so that individual pages or sites don't get as much attention or care?
13. Was the article edited well, or does it appear sloppy or hastily produced?
14. For a health related query, would you trust information from this site?
15. Would you recognize this site as an authoritative source when mentioned by name?
16. Does this article provide a complete or comprehensive description of the topic?
17. Does this article contain insightful analysis or interesting information that is beyond obvious?
18. Is this the sort of page you'd want to bookmark, share with a friend, or recommend?
19. Does this article have an excessive amount of ads that distract from or interfere with the main content?
20. Would you expect to see this article in a printed magazine, encyclopedia or book?
21. Are the articles short, unsubstantial, or otherwise lacking in helpful specifics?
22. Are the pages produced with great care and attention to detail vs. less attention to detail?
23. Would users complain when they see pages from this site?

After analyzing these 23 questions, as I expected, search engine is getting more humanize. Which means Google put their focus more on human rather than machine. If your SEO focuses on machine, you really have difficult to optimize your site each time Google rolls out new search engine improvements. But if your SEO focuses on human, basically you don't have to worry because each search engine improvements from Google, they focus more on human rather than machine.

My final advice is - Don't optimize your website for machine, do it for human.