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White hat SEO means you are not triggering Google guidelines and you must never manipulate with google search. White hat means you are helping Google in serving users quality product or content. There is no immediate effect when you run White Hat SEO but soon you get the results and they last long whereas Black Hat Methods cause a website die in a month or two + look into the industry you are in, analyze competitors' backlinks and you will see the way you should go to achieve good results

I am almost 100% sure it is spam attack of your competitors. Actually you should better quickly disable those links or you can be penalized by Google

White hat SEO means you are not triggering Google guidelines and you must never manipulate with google search. White hat means you are helping Google in serving users quality product or content. There is no immediate effect when you run White Hat SEO but soon you get the results and they last long whereas Black Hat Methods cause a website die in a month or two + look into the industry you are in, analyze competitors' backlinks and you will see the way you should go to achieve good results