Just like Earth blocks the Sun but, Sideway rays still Lights!
There are situations when you find huge traffic around an exact match search query and you have sufficient reasons to believe a good potential lies around but out of it.
Whereas, traffic around [keyword] is like a bull that will hit only the domain bearing that, or if they ever drift towards you they will bounce out instantly, but traffic slightly away from the exact match is ready to flirt with you, penumbra keywords match type is the way to go.
Most of the competitor’s brand keywords are the categories where you find such type of situation, traffic there is highly disinterested in what you offer & targeting them may mean burn out. But, people may be ready to turn towards you who are just out of this exact spot. They may be review seeker, people having complaints with the brand or something like that. They will listen and entertain you. Go for Brand-[Brand] targeting. It works!
Another situation where you may find it useful is, Location-[Location], targeting. Here, too [Location] may have huge traffic in which you may not be interested in, but search traffic region surrounding it may be of good interest for you. I myself have tried it in a travel campaign which seemed to have traffic only around the exact match and anything like, location travel, location holiday, location hotel failed to trigger ads due to low search volume. However, Location-[Location], targeting worked like a magic!
Penumbra Match Type Best PracticesThis kind of keyword-[keyword], match type should be practiced with utmost care. A Google rep. had cautioned me that, adding keyword as negative match, tells the system that you don’t want it. Since, you may be using the blocked word in some other targeted keywords, you should keep penumbra targeting in a separate ad group, so that it doesn’t at all interferes with others in visible or invisible ways.
Another point to note is that, you should not only set keyword-[keyword] match type, but should also eliminate different other keywords in such an adgroup which may trigger unwanted exposure. In this way you should refine your targeting.
Finally, don’t go for it without trying the keyword itself. Proceed in this manner stepwise:
photo credit: motjetom via photopin cc