Semicolon

DO use a semicolon between two independent clauses when they are not joined by a conjunction.

Sales promotions are good for inducing trial; they can hurt a low-quality brand.

DO use a semicolon to separate independent clauses joined by conjunctive adverbs (otherwise, however, accordingly, moreover, hence, ...).

The competition has a Web site; so, we've got to develop a site of our own.