Twitter's finally found a way to get important people to sign up

The former chief executive (CEO) of Pearson, Dame Marjorie Scardino, has just signed up to Twitter.

Why? Because Twitter has just appointed her to its board of directors.

67 year-old Scardino describes herself (on Twitter) as an "Education, technology and journalism dilettante" and "recovering CEO". She became CEO of Pearson - the FTSE 100 education and publishing company - back in 1997, stepping down last year.

In 2007, she was listed 17th on Forbes' 100 most powerful women in the world. Under her leadership, Pearson profits tripled to £942m.

Twitter, which went public this year, raising $2.09bn (£1.28bn) with an initial public offering, has been criticised recently for the lack of women on its board. Last month Sallie Krawcheck, a former Bank of America executive, said the absence was "a joke".

Scardino takes the number of people on the board to eight.