今天在用adword关键词工具搜关键词来着，看到右上角出现Announcements（3）的标志，很奇怪。开始还怕是自己的adsense账号被K了还是怎么着。点开后上边写着……写着啥的那个消息被我关了！大概是写着Try new Bid Type Target CPA and Max CPA.具体的我也找不到了，点 Learn more会到这么一个页面.
引用原文如下：
What is the new Bid Type advanced option of Conversion Optimizer (Target CPA and Max CPA)?
With the Bid Type option, you can select the method that suits you best when setting your Conversion Optimizer bids.
Target CPA
This new option allows you to bid based on the average amount you would like to pay for a conversion. For example, if you want to achieve an average CPA of $25, you could use this option and set your bid to be $25. Advertisers with CPA targets they would like to reach may prefer to use Target CPA so they can specify those goals directly.
Max CPA
With this option (previously the only option offered with Conversion Optimizer), you set bids using a Max. CPA. This amount represents the most you would want to pay for any individual conversion. The way a Max. CPA bid works is similar to the way a Max. CPC bid works. If you set a Max. CPA bid of $5, for example, the actual average CPA is likely to be somewhat less, such as $3. Likewise, a Max. CPC bid of $0.50 may result in an average CPC of $0.30.
To change your bid type to Target CPA, please follow these instructions:
- Select the Settings tab from within your Campaigns tab.
- Under the “Bidding and budget” section, click Edit to change your bidding option.
- Click Focus on conversions (Conversion Optimizer).
- Expand the + Advanced options section and select Target CPA.
Click Save to finish.
在网上搜索了一下发现google大概在2007就开始测试CPA了。可惜我现在还没确切的弄清楚cpa代表啥，action，是指打开广告页后再点击吗？还有回答有效问卷的数量?还是CPS比较直观一些。CPA会对adsense有啥影响，又或是有啥赚钱效应呢？
