The main objective of any blogger is to focus on increasing web traffic to his blog, so there is a need to follow some strict optimization rules, and SEO (Search Engine Optimization) one of them. Here are some of the best SEO plugins available in wordpress. If you follow them strictly, these plugins are sufficient for you to earn enough traffic from search engines, hence make nice online income.
1. All in One SEO Pack: This plugin will help you to set the info. like keywords, title, description, etc in any post or page, so its a must have plugin for WORDPRESS blog.
2. Google XML Sitemaps: Sitemaps help search engines to see the pages in your blog/website. Also they provide the details to search engine about the number of pages, new pages, change frequency, etc. This plugin generates a special XML sitemap which helps search engines like Google, Yahoo, Bing and Ask.com to better index your blog.
3. Keyword Statistics: This is one of the best wordpress plugin and you must have this in your blog. It checks the content of a post or a page for keyword-density (single words and optionally 2 and 3-word phrases; for each the 1-10 most commonly used can be displayed). It can update its information automatically while the author is writing his content in a variable interval (every 1-10 seconds) or manually by clicking on a button. The script comes with english and german stopwords, which optionally can be filtered out before calculating the keyword-densities. Moreover the commonest keywords are extracted in a list as a meta-keyword suggestion. Based on this list a description can be created and automatically set.
If you use these 3 SEO plugin efficiently then you are surely going to have huge traffic from search engines. Please comment if you have any doubts.