Where would you keep blackberries, if you had to tote up to 10 of them? In a Ziploc? If you’re carrying the smartphone, it’s a BlackBerry. If you have 10 of them, they’re BlackBerrys. Only the writers and editors on the Yahoo! front page feel they have the authority to change the spelling of a trademark:
To form the plural of a family name or trademark ending in Y, just add S. You don’t “change the Y to I and add ES” as you learned in second grade. So, the Kennedys, the O’Learys, and the Halle Berrys of this world all keep the Y in their name. Same goes for the BlackBerrys.