REDWOOD CITY -- Even as Oracle (ORCL) begins to reap the benefits of its move into cloud-based software, it continues to add to its portfolio through acquisitions, announcing the purchase of Eloqua for more than $800 million Thursday.Eloqua's cloud-based suite of marketing applications will "will become the centerpiece" of a new Oracle offering designed for marketing companies and departments, Thomas Kurian, executive vice president of development at Oracle, said in Thursday's announcement. The software giant agreed to pay $23.50 a share for the Virginia-based company, which Oracle said would mean a commitment of $871 million; the company sold