How do they do it ? i have heard of LSI but how can a machine read all the text in the articles and decide on its quality ? spell check,vocabulary .. do they check it ? If yes then .... how will they differenciate these 1) Original content with No Spelling Mistakes and good vocabulary . 2)Rewritten with No Spelling Mistakes and good vocabulary . 3)Original Content but with with few Spelling, Vocab mistakes . 4)Rewritten Content with No Spelling Mistakes and good vocabulary . 5) Mixture of all . How will they rate 5 of these kind of content .
Google will look at everything from Articles to Backlinks. Just make sure your articles are well written and formatted, and get good quality backlinks!