IBM said Wednesday it has acquired privately held Web conferencing company WebDialogs Inc. for an undisclosed amount.

    Billerica, Mass.-based WebDialogs has more than 500,000 users and offers online meeting and collaboration services that combine Web and audio conferencing.

    IBM said with the acquisition of WebDialogs it is adding a software-as-a-service delivery model to Lotus Sametime products. IBM also will integrate the service with its collaboration portfolio, including IBM Lotus Notes and IBM Lotus Sametime software.

    WebDialogs will become part of the Lotus unit of IBM Software Group.