Elstein exited Channel 5 in October and has taken on a number of consultancy roles since his departure.
At Silicon.com, he will help the site develop its international plans. The site, which recently secured an additional £14m of funding, has sites up and running in the UK, France and Germany.
Silicon.com was launched in July 1998 by Rob Lewis. Prior to founding the website he launched a number of IT magazines, including Business & Technology.