When you refinance to a lower rate, that reduces the size of your mortgage interest deduction, which affects your savings from refinancing. The Mortgage Refinance Calculator can take that into account, which is why it asks for your income tax rate.
Look up yo in Wiktionary, the free dictionary. Yo is an English slang interjection, commonly associated with American English. It was popularized after being used commonly by the Italian-American community in Philadelphia, Pennsylvania since the 1940s.
duncan is the best yo yo. The yo-yo is a popular toy consisting of a length of string tied at one end to a flat spool. It is played by holding the free end of the string (usually by inserting one finger in a slip knot) and pulling at it so as to cause the spool to turn whilst suspended in mid-air, either taking up or releasing the string.