To increase search engine ranking, we need to take care on metatag, look for quality link partner, keywords in paragraph, quality related info,

But some one say that if our website traffic increase, search engine ranking will increase as well.

Will that be true?

my answear would be yes, if your site is becoming on of the best in your area of stuff, it will also become the best on search engines

I dont think metatags really help any more maybe a few years ago but its mostly quality content, backlinks and traffic to and from your site.

I will try this.

I am sure traffic does play a part what part who knows. There are so many things that go into a good quality serp ranked site. Time is key imho if you want results fast do not bother time, time, and time.

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Im sure traffic makes a difference. My site got updated like every 5 months when it had barely any traffic now it gets updated almost weekely.