This skill of persuasion can be used to get better prices from merchants, and persuade others to do as you ask.
Level 100 Speech Glitch
To do this you need at least 25 speech. Head to Riften and go inside the Black Briar Meadery. Find the wood elf named Ungrien. Ask him to tell you about Maven Black Briar. Persuade or bribe if you are under level 25 speech. Rinse and repeat until you hit 100 speech. To accelerate this process, get the Thief Stone and be Well Rested for an experience bonus.