You may have heard something incorrectly.
"You currently viewing web page 4 of 8." is wrong.
"You're currently viewing web page 4 of 8." is correct. It means exactly the same thing as "You are currently viewing web page 4 of 8." The two words are said quickly together, they blend into one sound, and we spell it with an apostrophe to show that part of the word has been left you. "You're" sounds different from "you," but you may need to listen carefully to hear the difference.