The Fort Worth Symphony Orchestra launched a slick update of its Web site this week while also branching out onto Facebook and MySpace to reach some new audiences.  The handiest function of the orchestra’s new home page is its virtual seating chart. Rather than the staid, static online seating charts most of us are used to, this one allows the user to scroll over a photo of the inside of Bass Hall. As the cursor passes over a section (Upper Gallery, Mezzanine, etc.) the section lights up on the photo to show you exactly where those seats are. That should make for a more informed ticket-buying experience.