"Witches make far better Quidditch players than wizards, everybody knows that."
-- interview with Gwenog Jones in the Daily Prophet (DP1)
It has been said of Jones that "people who disagree with [her] have a nasty habit of turning into woodlice." She herself says that the Harpies "are easily the most exciting team playing," and added that witches make better Quidditch players than wizards. It is doubtful that anyone will disagree with her to her face (DP1). She is also accused of death threats against former team-mate Wilda Griffiths who defected to Puddlemere United (DP2). After a win following new Chaser Valmai Morgan joining the team, the Daily Prophet reported that Ms Jones said Griffiths was "lower than rat-droppings" (DP3). A riot during the game against Puddlemere United was blamed on Jones and she was said to be "helping the Ministry with its enquiries" (DP4).
Gwenog was a favorite of Horace Slughorn's while at Hogwarts. She was a member of his Slug Club. She still sends Slughorn free tickets to see the Harpies play whenever he wants them (HBP4, HBP7). He even invited her to one of his parties while back at Hogwarts during the 1996-1997 school year, and Hermione met Gwenog there (HBP14).
Ginny Weasley is a big fan and had a poster of Gwenog on her bedroom wall (DH7).
After retiring from the Holyhead Harpies, Gwenog took on the post of manager for the Welsh National Team during the 2014 Quidditch World Cup. When she heard that the manager of the Brazil team, José Barboza, had called her Chasers ‘talentless hags’ - a comment he claimed was taken out of context by reporter Rita Skeeter - she threatened to curse him. So it was no surprise that she was arrested after Wales lost their quarter-final match against Brazil when, in fury at the result, she cursed Barboza's face off in front of a packed stadium (Pm).
Talented Beater with a volatile temper - and she says what she thinks....
Other canon notes and references
"Wizard of the Month" for June 2004 on JK Rowling's website (JKR)
Gwenog is an invented Welsh-sounding name. Gwen is a girl's name meaning "white" or "fair" (from the masculine Gwyn = "white"). Og means "a harrow" or "plough", but "og" can also be added to some words as a suffix (eg. "sun" haul +og = heulog "sunny", "wind" gwynt +og = gwyntog "windy").
Jones is an extremely common Welsh surname, even though the Welsh alphabet does not include the letter "j"!
From the Web
Screenshots of the Daily Prophet's coverage of the 2014 Quidditch World Cup: http://imgur.com/a/AXutv