Pointcast Network is most probably ( ).

参考解析：

细节题。A项：研发出最新推销软件的公司；B项：促进公司网上营销的工具；C项：第一家使用网上推销软件的公司；D项：帮助公司进行推销的最流行软件。根据第三段software companies have developed tools that allow companies to “push” information directly out to consumers, transmitting marketing messages directly to targeted customers. Most notably, the Pointcast Network uses a screensaver to deliver a continually updated stream of news and advertisements to subscribers’ computer monitors可知，Pointcast Network能用屏保技术给订阅服务者推送新闻和广告，可见，应为一家研发出最新推销软件的公司，故本题正确答案选A。