
In the seventies and eighties, as songwriting lost some of its primacy, covers were common, but more likely to be recorded years after the 'original' version had been released. When Naked Eyes covered '(There's) always something there to remind me', their fans had to be told who Dionne Warwick was, much less Sandie Shaw, R.B. Greaves, or Burt Bacharach and Hal David. When Soft Cell tacked their cover of 'Where did our love go' onto their cover of 'Tainted Love', it was an exercise in new wave nostalgia.
The phenomenon of covers as homages during live performances has existed for a long time, too. Artists commonly take the live opportunity to perform a song they admire, by an artist they admire, as a way of paying tribute to their influences, or even just gratifying their impulses.
For the most part, calling something a 'cover' has denigrated it; it implies that it is secondary, unoriginal. Lately, though, the identity of cover versions seems to have shifted again, along the lines of live concert homages. Artists are regularly recording their own versions of originals that are brand new. In some cases, those artists are even invited to do so by the artists who released the 'original' version, and the cover version appears on the same single as the original.

The phenomenon is pervasive in the less-than-official realm; on a weekly basis cover tracks turn up on the blogosphere. This spring Arctic Monkeys did a bang up version of Amy Winehouse's 'You know I'm no good'. Two weeks ago 30 Seconds To Mars recorded possibly their best work to date - official or otherwise - in a rather unexpected gloomy head trip version of Kanye West's 'Stronger', on a live show.
The more common form of covers is alive and well, too; Mark Ronson's Version is an album's worth, and compilations like Nineteeneightyseven and Guilt By Association are devoted to them explicitly. But I am enjoying the phenomenon of the simultaneous tribute. The tone of these covers is somehow noncompetitive. There's a general sense of camaraderie, and artists don't seem to be threatened by them. They contribute to the general climate of cross pollination, as it were, in modern music, which can only be a good thing. And in some cases, they're a real treat.