We consider the Stone-Cech compactification beta S of a countably infinite discrete commutative semigroup S. We show that, under a certain condition satisfied by all cancellative semigroups S, the minimal right ideals of beta S will belong to 2(c) homeomorphism classes. We also show that the maximal groups in a given minimal left ideal will belong to 2(c) homeomorphism classes. The subsets of PS of the form S + e, where e denotes an idempotent, will also belong to 2(c) homeomorphism classes. All the left ideals of beta N of the form beta N + e, where e denotes a nonminimal idempotent of beta N, will be different as right topological semigroups. If e denotes a nonminimal idempotent of beta Z, e + beta Z will be topologically and algebraically isomorphic to precisely one other principal right ideal of beta Z defined by an idempotent: -e + beta Z. The corresponding statement for left ideals is also valid.