For example in https://www.google.com/intl/en/policies/terms/
Why does the text change from normal case, to all upper case?
Our Warranties and Disclaimers
We provide our Services using a commercially reasonable level of skill and care and we hope that you will enjoy using them. But there are certain things that we don’t promise about our Services.
OTHER THAN AS EXPRESSLY SET OUT IN THESE TERMS OR ADDITIONAL TERMS, NEITHER GOOGLE NOR ITS SUPPLIERS OR DISTRIBUTORS MAKE ANY SPECIFIC PROMISES ABOUT THE SERVICES. FOR EXAMPLE, WE DON’T MAKE ANY COMMITMENTS ABOUT THE CONTENT WITHIN THE SERVICES, THE SPECIFIC FUNCTIONS OF THE SERVICES, OR THEIR RELIABILITY, AVAILABILITY, OR ABILITY TO MEET YOUR NEEDS. WE PROVIDE THE SERVICES “AS IS”.
SOME JURISDICTIONS PROVIDE FOR CERTAIN WARRANTIES, LIKE THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. TO THE EXTENT PERMITTED BY LAW, WE EXCLUDE ALL WARRANTIES.
I thought, maybe it's to highlight important parts but I don't think so. A lawyer probably would think "the whole contract is important" and usually the least readable part is the one in all uppercase.
It is to my understanding if the first letter in a regular word is uppercase, it means it has a special meaning in the contract (usually more specific than it's general meaning). From Google's terms,
Thanks for using our products and services (“Services”).
So Services is strange as it has an uppercase S but I'm asking about entire blocks of text.