Since its earliest days, Google Inc. has largely promoted its search engine and search-advertising products through word of mouth and partnerships. But in recent months some of the Internet company's executives have been pushing for the company to overcome its aversion to paid advertising. That has created some conflict within Google, which is maturing and looking to reinvigorate its slowing growth. An episode around the Olympics earlier this year illustrates the tensions. Some Google employees were considering a plan to sell airtime during the NBC broadcast to other advertisers and to take out a spot to promote a Google product as well, according to people familiar with the matter.The idea didn't get past Google founders Sergey Brin and Larry Page, who felt a splashy television ad wouldn't fit with Google's image, these people said. A Google spokesman declined to comment. But there are signs that the internal debate is causing Google to shake-off of its reluctance to advertise. The search giant has recently held discussions with several Madison Avenue agencies, including Wieden + Kennedy and the boutique firm Taxi New York, about new efforts to promote some products, according to people familiar with the matter.