This is like advertising, but without the expense. It includes things like news stories about new products and services or unique ways in which they are delivered. An actor making the rounds of talk shows to plug an upcoming movie or a series of stories about a product recall are but a couple of examples. Since publicity is free, it is in great demand, provided it's good publicity. However, if good news travels fast, bad news moves even faster and tends to make a deeper impact. Just look at companies whose products have proven defective or dangerous, notable people who've run afoul of the law, or even neighborhoods perceived as being high crime areas.
Companies will frequently supply products to trade magazines, hoping those items will be favorably reviewed. That is certainly true within the Internet press. Several magazines have entire sections dedicated to reviewing the efficiency of the latest in servers, routers, or software applications. One positive review and write-up will generally lead to more, and there is a double benefit from the companies' perspective: their product got the equivalent of an expensive advertising campaign without the cost, and second, consumers were more likely to read about it because such articles are presented as information, not as sales tools. Is what your company offers the type commodity that is subject to product review? If so, be sure what you're selling lives up its expectations; bad publicity is difficult to recover from.