There are two very different ways to think about keywords on the Web: one is for writers and one is for researchers. Web copywriters are often advised to use keywords that customers type into search engines. Researchers, on the other hand, are told to focus on the words that customers actually use in online discussion forums.
What's the difference? In general, when customers participate in online discussions, they talk about their problems. When they search, they're searching for solutions.
The paradox for our purposes has nothing to do with the customer's use of two different sets of words. Rather, the paradox is this: a good blogger is both a writer and a researcher. So you need both sets of words.
The best bloggers listen to their audience and engage in online forums where their target readers are already congregating. How do you find those forums? By searching for the words your readers are using there: their problem words.
Think about what your customers say when they discuss their business pains. Plug those words into Google blog search, Twitter search and Boardreader. See what you find. Answer a few questions there, and then write a blog post about it. Use a few solution words when you're writing the post, and hyperlink those keywords to some additional online content.
Now, let me conclude with one very the big caveat. My favorite piece of advice about keywords kind of kicks everything I just said in the head. It comes from Scott Stratten of Unmarketing fame who says, "Nobody looks at a post and goes, 'That was a pretty bad post, but it was really keyword rich, so let me pass it along." Nope. Nobody does that.
The point here is that your content has to be useful and interesting to read, or it doesn't matter how many people get to it via search. Visitors have to like it, bookmark it, want to pass it along, or - at the very least - want to continue reading past the first sentence for the post to make a difference.
So use those keywords - both sets - but have an opinion first. Or be interesting. Or share something with readers that makes them think. First and foremost, be useful.