Through his writing, Shakespeare added many new words and phrases to the English language. Many of which we still use today, like “heart of gold”, “piece of work”, “fight fire with fire”, “wear your heart on your sleeve”, “vanish into thin air,” etc. And that’s just a small sampling of phrases, there are many more. (Check out this awesome image  if you want to see more phrases that were added to English by Shakespeare.
I think if you just look at the listing I’ve included that it is easy to see how the writing by people of today could have a Shakespearean quotient. Well this site, has an application that will test your writing for similarity to the 1916 edition of The Complete Works of Shakespeare.
What they have done is compiled a list of all the unique words and turned it into a database that the application uses to decide how similar your writing is that edition of Shakespeare’s work. Note that if you cut and paste passages from Shakespeare’s work off of the internet it may not generate a 100% result. This is because the text you find online might not be from the 1916 edition.
I copied and pasted an essay I was working on for school and got a 92 %. Then I copied and pasted an article on knitting and was surprised to get a 72% when I thought it would score much lower. The fun part is each percentile has a different saying attached to it. The 92% asked me: “Do you live at the Rose Theater?” And the 72% told me to “feel free to start comparing myself to a summer’s day.”
Overall, this is a really fun application. I hope you’ll get a kick out of comparing your writing to Shakespeare’s. I know I did!