Not that anybody doubted it, but Oprah's bookish influence extends all the way to the mass market lists, as evidenced by this week's #2 title. The Deep End of the Ocean, Jacquelyn Mitchard's debut novel, which made a resounding splash as Oprah's first pick for her book club-30 weeks on PW's hardcover list, with more than 915,000 copies in print of the Viking hardcover -- looks set to repeat its success. Signet's paperback edition of this wrenching novel went on sale June 3 with 1.7 million copies in print. According to Signet publicity director Larry Hughes, Mitchard has "a steady stream of appearances and speaking engagements into the fall." The author's fans won't have long to wait for her next effort: Viking will publish The Rest of Us: Dispatches from the Mother Ship in November -- a collection of pithy pieces from Mitchard's nationally syndicated column.