Short answer is yes, it is vital to great marketing to have a clearly defined target market.
If you target just anyone, your message will be heard by NO ONE!
Think of this simple example.
You stand up on top of one of those flat benches that you try to sit on and are so hard on your butt.
And you yell out..
“Hey, you need new shoes, there are some here that are just perfect for you!”
Will anyone in that crowded mall think you are talking to them? I doubt it.
Maybe the odd person will look down at their shoes and think, yes I should go buy some new shoes.
But that is not really helpful to anyone.
Now imagine you say the following…
“Hey, young man skateboarding by me, I see your shoes are wearing out, your should come in to this store and get new skate shoes that will improve how good you will ride and also look very awesome”
Do you think that will get a response…..
And – if you really know your target market (i.e. have a list of prospects and customers with names, info and more) you can say this…
“Hey Craig, slow down on that skateboard, and come look at the newest line of skate shoes. Your toes are coming out of those ones, and the girls will love the tricks you do with new grip on your board….”
Does that not make so much more of an impact?
The more specific you can talk directly to your target market, the better your message will be.