谷歌AdWords关键词工具（AdWords Keyword Tool）https://adwords.google.com/select/KeywordToolExternal
关键词映射工具（Keyword Mapping ）http://www.kwmap.com/
关键词追踪者（Wordtracker）http://www.wordtracker.com/
关键词间谍工具（Keyword Spy ）http://www.keywordspy.com/
谷歌建议（Google Suggest）http://www.google.com/webhp?complete=1&hl=en
关键词竞争（Key Compete ）http://www.keycompete.com/home.asp
数码关键词建议工具（Digital Point Keyword Suggestion）http://www.digitalpoint.com/tools/suggestion/
关键词精英（Keyword Elite ）http://www.keywordelite.com/index1.htm
优质关键词（Good Keywords ）http://www.goodkeywords.com/
关键词发现工具（Keyword Discovery ) http://hosting.fastdomain.com/
