Hyperfoliations on compact 3-manifolds with restrictions on the external curvature of leaves

$C^\infty$-foliations of codimension 1 on compact Riemannian 3-manifolds are studied. New classes of foliations, namely hyperbolic, elliptic, and parabolic foliations, are considered. Examples of such foliations are presented. In particular, a $C^\infty$-metric of nonnegative sectional curvature on $S^3$ such that the Reeb foliation is parabolic with respect to this metric is constructed. Analytic 3-manifolds with sectional curvature of constant sign admitting parabolic foliations are classified.