Over at MarketingProfs, Scott Baradell offers us Link to Eight Telltale Signs That Your Press Release Is Bullshit (his term, and an apt one). But don't skip this just because you don't do PR: signs 1 through 6 apply to any kind of communications.
Three of them deal with different aspects of the same issue: bad writing. Specifically, industry jargon, pointless superlatives (or is that the groundbreakingly, industry-changingly pointless superlatives), and vacuous business phrases.
The industry jargon item is a tricky one, actually; you want to speak the language of the industry of your audience, to show that you understand it. But you need to think about whether people outside the industry will be reading - and whether perhaps something different ought to be written for them. And (as Scott points out) you'd better use the jargon correctly, or you'll really blow it.
It makes a handy checklist for any kind of marketing writing; take a look.