Q: Are pingbacks sent immediately when a post is published, or are they scheduled as a cron job? If the later is correct, how often does the job run and can I trigger it manually?

A： 您可以安装core control (wordpress plugin) 了解更多信息。

Q: Are there any other terms for PBs to be sent besides having "Attempt to notify any blogs linked to from the article" set to on, and of course a link to another blog in the post content? (for example, should the sender post be public and not private? should the blog be non private?)

A： Wordpress可以也不关心外部资源作为某种程度上未定义的术语是公共的还是私有的。

Q: Should the outbound link be placed in the post content or can it be placed in a custom field of the post in order for the PB to be sent?

需要将其放入内容中。

Q: In case PBs are not sent nor received in my blog, what is the best way to debug and detect the problem?

记录并分析站点的入站和出站网络流量，重点关注HTTP请求，以了解到底发生了什么以及可能出现的错误。此外，我上面链接的核心控制插件可以帮助进行与cron相关的调试。