Marketing objectives can only be met through reaching out to your target audience and conveying your brand message.
Promotional activity enables you to make the connections that turn into leads and sales, so the way you promote your brand is vital.
Here's a few examples of what your brand should be trying to achieve through promotional activity:
Consistency - The channels and way you promote your brand should be consistent with your brand image. If you were a "young and trendy" energy drink, it would make sense to run a Facebook ad campaign to reach your target audience for example.
If your brand has a more serious tone, for example a chain of funeral homes, a Facebook ad campaign might be a waste of money because the medium you are using to promote yourself doesn't resonate with your overall image.
Reach - Effective promotional activity is about two things: Making sure a large number of people hear your message, and making sure those people are targeted and relevant to your brand. Marketing inefficiencies can spiral out of control if your promotional activity doesn't consider who and how it's reaching out to people.
You want to be selling the value of your brand to the "right audience" - and promotional activity is key in this area.
Repetition - Telling someone how great your brand is just the once often isn't enough.
To market a product effectively, you may find that communicating continuously over a period of time is the only way to drive the message home.