Online magazine “Mr. Showbiz,” owned by Microsoft co-founder Paul Allen’s Starwave Corp., will handle Web coverage of this year’s Sundance Film Festival.According to Starwave, “Mr. Showbiz” highlights are slated to include a scorecard of films’ plot synopses, likely marketing angles, and story strengths and weaknesses. The Web site (http://www.MrShowbiz.com) will also include interviews with festival participants and news from parties and screenings. The first slated interview is a conversation with helmer Richard Linklater, whose film “SubUrbia” opens Jan. 17. The “Mr. Showbiz” site is edited by Susan Mulcahy, former New York Post and New York Newsday columnist and former editor of Avenue magazine.