Did you ever ask this? Why some of your blog articles are are not indexed by Google? Although you have already registered your blog to Google? This can happen because excessive SEO optimization. Excessive SEO optimization include: 1. Too many keywords repeated 2. Page title is not match with the contents of the article or no recurrence at all in the article 3. Articles are the result of plagiarism (copy-paste) 4. Too many articles published in a day with almost the same title. This usually happens to those who follow or pursue SEO contest. 5. You change the template too often. 6. Mixed blog or articles are not in the same topic.