Ad sales have always gone up and down with the economy.

VOA: special.2009.03.21

There will always he suggests appear to be something ad hoc about the methods used in the study of politics.

主题允许多少精准性？我们如何得知,事情总有，他也提到,总有一些事是特别的。

耶鲁公开课 - 政治哲学导论课程节选

Mitchell says that DoubleClick has always promised ad networks that their data would not be shared or used to work with advertisers and publishers directly.

FORBES: Google's TroubleClick

An eBay-style bidding system means prime ad spots always go for the lowest price, minimizing ad spend.

FORBES: Selling Out Or Growing Up? Why Paid Social Media Is Set To Surge

The other reason the year of the mobile ad always seems to get pushed out to next year?

FORBES: Google: Here's How Well Mobile Ads Can Work