When we first heard about rocker John Mayer's recent decision to sign a deal to sell adspace within his twitter feed, we thought it was a joke - Mayer's sense of humor is well-established. On the other hand, we thought, it's still a month yet before April Fool's day.

Then we saw his next tweet, and with a horrible sick sense wonder, came to the realization that he's NOT joking - John Mayer is actually endorsing products like Campbell's soup on his Twitter feed.

The Twittersphere has taken notice, and reactions have been less-than-favorable. Indeed, with headlines like Twitter Whoring Goes Mainstream, the general consensus seems to be that Twitter-based endorsements rank on the decency scale somewhere between clubbing baby seals and being Lee Iaccoca.

But is it really so clear-cut? What's the big deal about Mayer selling ad space? Isn't this the corner that the RIAA has been saying that music piracy will force artists into someday?

Perhaps the answer lies in the nature of the products that Mayer has, so far, chosen to endorse. The fact that John Mayer (allegedly) eats Campbell's Soup makes absolutely no difference on the quality of the man's music; indeed, were I to eat Campbell's Soup for every meal of every day of my life, it would at no point be the direct cause of any musical success I might achieve.

Perhaps if Mayer were endorsing relevant products, people wouldn't be so up in arms about it. If he was, say, endorsing a particular piece of musical software or equipment, users would benefit from his advertisements as much as they generally benefit from following his Twitter feed. It's the apparent randomness of the endorsements that got my back (and, I assume, the backs of some other critics) up.

My stance? Twitter endorsements are all very well and good, but only when they're on topic. I don't follow John Mayer's Twitter feed because I care what kind of soup he eats, or what brand of cookies he likes to snack on. I follow him because he's a musician, and I'd be perfectly happy to take advice from him about musical equipment or, indeed, anything remotely related to the industry that made him famous. Selling soup ads just makes him seem desperate - and that's never a good thing.