==WTF?== 
 "The covariance of a variable with itself (i.e. X = Y) is called the variance" 
 You can't tell me that sentence makes a damn bit of sense.  
 It also contradicts: http://en.wikipedia.org/wiki/Variance, which says "The variance is a measure of how far a set of numbers is spread out". 
    
 ==WTF#2== 
 "The correlation of a variable with itself is always 1" 
 a) How can something correlate with itself? Ah, waitit is just terrible grammar.  
 "...(except in the degenerate case where the two variances are zero, in which case the correlation does not exist)" 
 b) What is a degenerate case? At least give either an example or a link to what you are talking about.  
 c) How can a variance be zero? 
 d) Correlation does not exist, or is equal to zero? (Very different, those two).