Is it okay to vacuum a laptop keyboard? Would it cause any damage?


Question: Importance of dividend yield when evaluating a stock?
Answer: 
  But I wish to know why the parameter is dividend/market price rather than just 'dividend'? What 'extra' info you can uncover by looking at dividend/market price that you cannot get from 'dividend'?


Consider two stocks A and B. A offers a dividend of $1 per year. B offers a dividend of $2 per year. Let's remove all complications aside and assume that this trend continues. If you were to buy each of these stocks you will get the following amounts over its life (assumed infinity for simplicity):


  cash flows from A = $1/(0.04) = $25, assuming risk free is 4% per annum
  
  cash flows from B = $2/(0.04) = $50, assuming risk free is 4% per annum


The price you buy them at is an important factor to consider because let's say if A was trading for $10 and B for $60, then A would look like a profitable nvestment while B won't. Of course, this is a very simplistic view. Dividend rates are not constant and many companies pose a significant risk of going bust but this should help illustrate the general idea behind the D/P ratio.

P.S.:- The formula I have used is one for computing the NPV of a perpetuity.