Google "Pure spam" problem 2016-05-26 02:38
Last week I found my site disappear from Google search result. I tried search "site:www.henryxi.com" but nothing there. A day later I received the message from Google Search Console. To my surprise, Google prevented my site because "Pure spam". The whole message is here
Google has detected that your site violates our Webmaster Guidelines. Because this critical issue lowers the quality of search results for users, Google has prevented the offending pages from showing in Google Search results. This manual spam action has been applied to henryxi.com/ . To reinstate your site, you must significantly change the content to conform to our guidelines. Only after making those changes should you submit a reconsideration request in order to have your the content included in Google Search results.
I don't know what is "Pure spam". Every article is original in my site. I begin asking people in productforums.google.com. At the beginning I think the reason Google ban me is that I add js plugin(code-prettify) to pretty the code in my article. But when I remove js the problem is still there. At this time someone told me my 404 page is not the really 404 page. For example when people request any non-existent url in my site will get a response with 200 http code. So Google think my site is "Pure spam". After adding 404 code for non-existent page the problem solved.
when you get "Pure spam" problem, the first thing is to ask yourself "Did I generate useless page or copy others' article ?". If not you should check your error page(404,500 etc.). If response of these page is not the correct http response code you should fix it immediately.