We show lower bounds of Ω(n) and Ω(n1/4) on the
randomized and quantum communication complexity, respectively, of all
n-variable read-once Boolean formulas. Our results complement the recent
lower bound of Ω(n/8d) by Leonardos and Saks and
Ω(n/2Ω(dlogd)) by Jayram, Kopparty and Raghavendra for
randomized communication complexity of read-once Boolean formulas with depth
d. We obtain our result by "embedding" either the Disjointness problem or its
complement in any given read-once Boolean formula.Comment: 5 page