black dog
yellow dog
ugly dog
and use {KeyWord:Dog}. If they enter one of the three possibilities it will show them. If not, eg hot dog, it will just show Dog.
What you certainly DONT want is ads which show exactly what the user typed, with no control over it by you. What if they typed something offensive related to dogs?
Use it for situations where you have keywords
black dog
yellow dog
ugly dogand use {KeyWord:Dog}. If they enter one of the three possibilities it will show them. If not, eg hot dog, it will just show Dog.
My experience of using dynamic keywords is slightly different. In the above example, supposing that "hot dog" was broadmatched to "ugly dog" the keyword "ugly dog" would be inserted. To get "dog" to show you'd have to have it in the keyword list.
Suppose we have the following keyword list:
black dog
yellow dog
ugly dog
very ugly red and yellow dog with pink spots
and we use [KeyWord:Dog}. A search for "black dog" will show "black dog", a search for "green ugly dog" will show "ugly dog". A search for "dog" might trigger any of them, or even none (depending on how broad google was interpreting broadmatch). A search for "very ugly red and yellow dog with pink spots" would show "dog" because the keyword is too long to insert.
Likewise on the content network, you'd likely get "dog" because no specific keyword is triggering the ad.