Every Words With Friends Game has 104 tiles and 2 of those tiles are blank. Blank tiles carry no point value but can become any letter you wish, making them useful for completing words that wouldn’t have been possible otherwise. Even blank tiles placed on a double or triple-letter square are zero.
Blank tiles can still influence score. Placing a blank on a double- or triple-word square (DW, TW) the value of the word is still doubled or tripled, even-though the blank tile hasn’t added anything to the total score of the word.
Another good place to use a blank tile is to make a previously played high scoring word plural by naming the blank tile as an “S” if possible. Or use a blank tile to replace a low scoring letter needed to complete a long word with high scoring tiles such as “Q”, “X” or “Z.”
The blank tile is also to useful to assist with building 7 letter word combinations, or bingos. Bingos require the right mix of skill and luck and when played receive an additional 35 points added to the word score.
A blank tile, once played, becomes that designated letter on the board for the remainder of the game.
It may be useful to remember if your opponent has played any blank tiles during the game. Because there are only 2 blank tiles you can begin to make assumptions of what tiles they may have and avoid leading them into easy high scoring words.