Late yesterday, the company announced plans to add support for the open source Open Document Format–a rival of Microsoft Word–to Office 2007. Beginning with Service Pack 2 for Office 2007, due in the first half of next year the market-leading productivity suite will offer ODF as a default file format and Adobe’s (ADBE) PDF (Portable Document Format) and Microsoft’s own XML Paper Specification as well. “We have heard from customers and governments that they would like to see us do this,” said Tom Robertson, general manager of Interoperability and Standards at Microsoft. “Now is the time to announce this support.”

“Now,” of course being short for “now that the European Commission is investigating us again over claims of monopoly abuse;” “support” short for “poor support.” At least that seems to be the position of the European Committee for Interoperable Systems, which is openly skeptical of Microsoft’s sudden commitment to genuine interoperability. “It is particularly striking that all of Microsoft’s latest policy statements on interoperability are still in the future tense, as though these were difficult technical objectives,” said ECIS spokesman Thomas Vinje. “They are not. A closer look at their substance suggests that Microsoft is still playing for time to further consolidate its super-dominant position, and that continued antitrust vigilance will be necessary.”

And continued antitrust vigilance is what Microsoft’s going to get. This morning the EC said it had “taken note” of the company’s announcement and plans to study it. Said the EC, “In its ongoing antitrust investigation concerning interoperability with Microsoft Office, the commission will investigate whether the announced support of ODF in Office leads to better interoperability and allows consumers to process and exchange their documents with the software product of their choice.”