“Ask Someone Why They Love Their BlackBerry” is a classic nightmare for anyone who cares for grammar.

It’s main problem is with the disagreement in number: “Someone” and “BlackBerry” are singular. “They” and “Their” are plural.

The correct versions of this sentence are:

“Ask Him Why He Loves His BlackBerry.”
“Ask Her Why She Loves Her BlackBerry.”
“Ask Someone Why He or She Loves His or Her BlackBerry.”
“Ask Everyone Why They Love Their BlackBerrys.”
“Tell Me Why You Love Your BlackBerry.”
“Tell Everyone Why You Love Your BlackBerry.”

Each of these raises challenges with content, so the writer sacrificed number agreement.

In the coming years, I’m sure, the writer’s problems with number will no longer be a problem. Languages evolves. Doesn’t they?