Document ai:noinject feature: prevent automatic injection in node body of selected nodes.

This should be migrated to a per node setting

A feature which allows creation of content that will have no ads inserted (defeat automatic triggering).

If the node body has the string ai:noinject anywhere within the first 512 characters, no automatic injection will take place.

Ideally, you'd put a HTML comment at the start of the node body, like this:

<!--ai:noinject-->

But, the Drupal HTML filter strips all comments, so that won't work in most cases.

I usually use something like this:
<br class="ai:noinject"/> or <h3 class="ai:noinject">Heading text</h3> somewhere in the first few paragraphs. The only problem with this is that it may not be valid CSS, which may trigger CSS validation errors if you're persnickety about such things.