Writing headlines is an art. We all have memorable ones lodged in our journalistic (sub)conscious. My own personal favorite at the moment is from the South African "Daily Sun" : Evil cows ate my garden.
A lot has been written about how headlines that work on paper will not work on the web. Amy Gahran, Jakob Nielsen, New.Journalism.Review, Paul Bradshaw et al have written on this. The consensus seems to be (and I agree) that as search engines are such an important driver of traffic to sites then headlines need to be formed in such a way that they give important geographic, subject and object information. Readers tend to scan rather than read, look for names of places rather than puns on places and may not be up on local slang. As Harald Evans wrote: "writing good headlines is 50% of the text editors' skills".
This is where some of the problems arise. In the courses i give there is inevitably quite a bit of push back to this. There is a fear that one of the few areas of joyous creativity in a subs daily routine will disappear. The ability to craft a punny headline is a hallmark of a brilliant sub. If headlines have now to be so prosaic that they will appeal to the pragmatic algorithms of the search engine, then wont that mean that the art will wither and die? It is an argument I can understand (though not agree with). But different platforms need different vocabularies.
And here's the thing. Services like Twitter and Jaiku and others are not the web. They are not search engine dependent. They are more emotional and less analytic. Because you chose to follow to a particular entity (person or service) then the context is already given. So witty headlines will work. Not only will they work, they will be appreciated as the short verse poetry they could be.
So subs, sharpen your similes, ramp up your rhetoric, mix your metaphors and get in the game. We need you. We want you.