If you have better tricks for writing ads go for it. Hopefully you'll share it here. I know I'm not the greatest copywriter so putting in extra keywords is kind of a good crutch for me.
It's all relative. I always see one when I log on to myspace for what must be a quiz site. It goes something like this:
ARE
you dumb?
Take our quiz and find out.
Or something like that. While I like the idea of what they're doing and I have no doubt that they are getting clicks, it irks me because I think it can be done much better in that it will attract more attention. Something like,
DUMMY
Yeah, you.
Share your high score from this quiz.
or something equally lame sounding but will guarantee clicks from the mindless myspace crowd.
However, when attracting a more "sophisticated" browser, (i.e. one that is actually looking for something and not just clicking mindlessly like myspace users) I've found that keywords mixed with a very "solid" statement works best, particularly for Adwords.
Say your keyword is "gay forum."
Gay Forum for cock!
Read this gay forum
and you'll get pounded by the best cock!
I could write something more compelling if I had the initiative - and possibly if I was gay, but you get the point: make a bold statement with your limited text. I don't even mind embellishing a bit or even a lot. Hell, they aren't going to remember the ad that brought them to the page. Just be smart about it. Think about your user and why they are searching for what you are selling.
BTW, Shoe's Arrow message is gold.