Only if they disclose that they are employees of the company. The Federal Trade Commission has issued rules that require product endorsers to be clear about their connection to the company that makes the product. For example, if a company sends out free product samples to bloggers, in the hope that they will rave about the product, the bloggers must disclose that they received the product free. Similarly, employees must reveal their employment relationship whenever they review or endorse their employer's products. The purpose of these rules is to allow consumers to make an informed decision about how much weight to give a particular endorsement. For more information on these rules, as well as sample policy language you can use at your company, see Nolo's article Employees' Online Endorsement of Company Products.