There is a whole business culture surrounding the Blackberry.

It is often the mark of seniority having one in business.

Once you have one it is most important to flash it around.

It gives the owner the right to expect quick fire responses to his whims.

Typically, owners of them become thoroughly objectionable. They fire out demands 24/7 and expect immediate responses. They grow increasingly angry when their requests are not answered immediately. 

They are best avoided at all costs.

When a lady manager of mine got her Blackberry, she immediately visited Harvey Nicks in Leeds to purchase big brand Blackberry bag that cost almost as much as the Blackberry.