Know your primary audience. Allow for other audiences, but know who you are writing to. The audience for a science paper may be other researchers in your field, researchers in associated fields, or other fields, other scientists, or a more general audience. Audiences for hackers might be other hackers, programmers, computer scientists, users, investors, salespeople, technicians, translators, etc.

Pick one main audience, and a very few related audiences, and write so that any of them can understand without confusion or distraction. The red herring for an IPO does not benefit from leet-speak, nor does the FAQ for an online service benefit from legal disclaimers.