People on the Move: Pam Hamlin becomes Global President of Havas' Arnold Worldwide, Twitter appoints its first female board member, and Erwin Penland receive Saatchi exodus

Gumtree has brought in Andrew Hooks as director of motors as part of its plans to expand into the motor industry. Hooks, who joins from eBay where he was head of business for motors and electronics, has been tasked with developing the site for private sellers as well as improving the professional dealer experience.

Specific Media has announced the appointment of Roly Elliott as director for trading and strategic partnerships, ahead of company plans to bring new opportunities to market. Elliott joins from MEC where he was part of the MEC Global Solutions team.

PHD Worldwide has appointed Patrick Ryan to the role of worldwide business development director, joining the agency from Universal McCann.

Betfair's director of digital, Ben Carter has left the online gambling firm, to join gift website Not On The High Street. Carter, who has worked at the Hammersmith headquartered company since October 2009, left his role on 6 December to become marketing director of Not On The High Street.

PR agency Grayling has appointed Peter Harris as its USA CEO, starting from 1 January. He joins the agency from MSL.

Starcom MediaVest has announced the promotion of Andrea Brown from head of SEO to managing director of its content arm, LiquidThread. This move follows the appointment of Olivier Gers as global president of LiquidThread in October.

MediaCom has announced the appointment of Ben Phillips as its first global head of mobile, with the aim to focus on mobile strategy directly with clients. Phillips was previously commercial director at mobile demand side platform Adloqi.

Erwin Penland has announced the appointment of Con Williamson, currently creative chief at Saatchi & Saatchi’s New York officers, as its new chief creative officer. John Dunleavy, MD on Saatchi’s Miller business and an executive creative director on Lenovo, John Cornette, are also set to leave Saatchi & Saatchi for Erwin Penland.

Tangible has promoted its chief operating officer Karen Trickett to CEO, managing its three offices across London, Edinburgh and Cheltenham. Trickett, who has recently overseen a restructure to bring the three offices in line together, has also hired Paul Becque from Elvis as chief strategy officer, Jimmy Thompson from Havas as creative director Cheltenham and Claire Frankling from MBA as client partner.

Air Partner has announced the appointment of Kiran Parmar as group marketing director, where he will look to grow the brand globally.

Hill+Knowlton Strategies has announced the promotion of Ian Withington from managing director of H+K’s food and drink team to group managing director.

Ogilvy has appointed André Laurentino, currently executive creative director at TBWA/London and global creative director for McDonald’s, as global executive creative director for Unilever.

Former Playtech commercial director Adele Lawton has been named Betfred.com’s new head of online marketing. Lawton has 15 years’ experience in the gaming sector and spent three years as head of Jackpotjoy before joining Paytech, as well as stints at BskyB, bet365 and Gala Coral.

Sydney’s Ogilvy One has appointed Melissa Warren as its senior strategic planner, together with Andrew Braithwaite as strategic planner.

Aegis-owned media agency Carat has appointed MediaCom's Alex Crowther as its new global client president, responsible for managing the $3bn General Motors account. Crowther, who was previously MediaCom's Asia Pacific CEO, takes up the new role in Detroit right away.

Digital media agency 7thingsmedia has announced the appointment of Sarah Pettay as client services director, joining from Group Commerce, Inc. where she held the role of director of partner management leading its e-commerce and mobile apps proposition.