The issue is around legitimacy, or even honesty (well, I need a better word, I mean honesty as in "an honest mistake").<p>1) As a reader of the email, the misspelling could have occurred honestly as a mistake, or be a manipulation.  I don't know, as a reader, which is which.  One one hand, it's sloppy, but on the other, adds an air of humanity (this all starts to smack of a mini Turing test).  I don't really see it as "co-opting the language"; did he mispell the product "BoBos" as "Boobs" to capture my attention?  He didn't really create a new word, as much as use a style designed to draw attention.  I see it similarly to caps in The Wrong Place, for example.<p>Vs.<p>2) The Re:, on the other hand, as a user, _cannot_ happen honestly, since AFAIK, I didn't send a mail.  You excuse the  Re: by assuming some implementation details "not in evidence".   When I request the price list, I entered info into a cloud, and an price list appears in my mail.  I didn't send an email, I entered a form.  If it sends a mail to a rep vs. entering a db record vs. passing a tweet, that's all just server stuff hidden from me... and if it does send a mail "on my behalf", that's no excuse to put the Re:, since the developer _knows_ the user didn't send the mail, the system used it as a messaging queue.<p>Things evolve.  Before twitter, people didn't litter their text with hashtags.  Now, those have new meaning.  And if we feel that adding "Re:" to a subject line no longer means "I'm responding to a direct email I was included on", that's interesting to learn.  It would be even more interesting to see, perhaps via a broader survey, if most recipients actually find it misleading, while others find it clever enough that it enhances their odds of buying the software.  The author only gives us the "positive impact" side; we don't know if he's scaring away potential customers who would have purchased by use of this tactic.  That is, it's not necessarily "incremental" sales, it's a different group of people who are responding (and perhaps larger than the group responding to the original version, since sales are up).