The CAPITALS highlight key points. It is similar to the newspapers and magazines where they put quotes into boxes or highlight paragraphs with a headline.
It means that you can speed read the capitals to get the sense of a large block of text. Then if you find the subject matter boring you can not read the whole piece.
It is like a KEY POINTS presentation.
That is why if you write like this you generally get a bigger impact from those reading because more people can quickly scan your post.
Lets be honest many people dont want to read loads of text these days !!!
It is not SHOUTING - because if you read through my posts you will see I capitalise KEY WORDS and names of SUBJECTS in the posts.
I have decided to finally come clean about this - because I think I do owe an explanation to all you good folks on this forum for being patient with my style. Thank you. So now you all know

I also dont expect you to take this approach - but hey you may like to now you know WHY !