The goal of the copy is to connect with the reader, and guide them towards an action.

"Human relationships are about communicating. Business jargon should be banished in favor of simple English. Simplicity is a sign of truth and a criterion of beauty. Complexity can be a way of hiding the truth."
- Helena Rubinstein

Using complicated, fancy words does not make you seem any smarter or your solution any better-it just turns everybody off. Who wants to read something that doesn't feel like it's written for them? Talk to people like a real human. If you wouldn't use a phrase on your website in a conversation with a customer, then don't use it.

In addition to fancy words, avoid meaningless phrases. What do "on-demand marketing software", "integrated solutions" or "flexible platform" really mean anyway?

Or useless phrases like "changing the way X is done", "paradigm shifting …" or "exceeding customer expectations"-stop the nonsense. These bland phrases have long lost any meaning, and you will just waste precious attention time. You can see a list of the top 100 most overused buzzwords and marketing speak in press releases here.