Presumably frustrated by the relatively tiny audience for his online "webcasts," Sam Donaldson may be considering airing his own radio talk show. Donaldson, whose last "daily" Internet commentary was posted on June 29, told Mediaweek that his recent fill-ins for top ABC talk personalities are "not a lark. ... The more I do it, the more I like it. I'm having a ball, and if I can attract an audience, I'm ready to compete." Last year Donaldson stepped down as co-host of ABC's 20/20.