He is the second senior figure to leave the publisher's digital team in recent weeks, following search engine optimisation specialist Netrank's poaching of Lucy Allen, Future's head of new-media sales, as managing director.
The publisher is gearing up for a major online push in 2007, with £6.7m earmarked for web investment, which will account for more than half of its new product development.
Following the development of two technology portals - techtested.co.uk and techdaily.co.uk - Future plans to launch a music-making community site called musicradar.com and a cycling website, bikeradar.com, within the coming financial year.
The publisher said that further print and online developments will come from its core areas rather than through acquisitions or new sectors.
Isporty.com, which will be launched on 8 January, is the brainchild of Chris Ward, founder of youth marketing agency Beatwax, which promoted the launch of Friends Reunited.
The site will host club pages and promote local sports and will enable users to post and share photos and videos of their matches.
Ward has signed the England football team's assistant manager, Terry Venables, as a sponsor, and Mike Lee, director of communications for London's 2012 Olympic bid, as chairman.
Maher-Roberts joined Future as a journalist, progressing to several senior roles, including publishing director of its computer games magazines. He also founded customer publishing arm Future Plus and led the acquisition of foreign brands as head of international developments.
Future has begun the search for successors to Maher-Roberts and Allen, and has also created the role of chief technology officer to drive forward its digital plans.