Congratulations to Matthew O’Riordan at Lemon Foundation, which has offloaded subsidiary Lemon Traffic to Operative, the online advertising operations firm.

Operative has acquired all the assets of Lemon Traffic, though despite a little arm-twisting Matt has refused to reveal the terms of the deal.

Lemon Traffic was set up earlier this year as a division of Lemon Foundation, which is owned by Matt (who is an E-consultancy founder and shareholder).

Operative CEO Michael Leo explained the reasoning behind the deal: “Our long-term expansion strategy requires us to keep up with the growth of the online ad operations market.”

Leo believes that the European online ad landscape is really motoring: “While the growth in the US has been substantial, the growth throughout Europe has been accelerating, necessitating this consolidation and perhaps others to come.”

Operative’s clients include websites such as The Economist, The Wall Street Journal, AOL, MSN, Business Week and iVillage.

Lemon Traffic’s MD Joni Mallett departs to take an in-house role with Mediarun.