YSK Yelp replaces restaurant phone numbers with a special number that charges that business a marketing fee. If you find a good restaurant on Yelp Google their phone number instead so they don't lose any money.
from /r/YouShouldKnow
YSK Yelp用一個特殊的號碼代替餐廳的電話號碼，向該企業收取營銷費。如果你在Yelp上找到一家好的餐廳，可以用谷歌搜索他們的電話號碼，這樣他們就不會損失任何錢。