one from my e-food HBS Working Knowledge: Career Effectiveness: Audience Grabbers: Start With a Bang
- though written about presentations, alot of these seem to apply to online presentation too
1. Make it personal
2. Throw out a quirky fact
3. Put them on the edge of their seats
4. Draw a hypothetical scenario
5. Create a series of vignettes
6. Use a pertinent quote
"A lightning roundhouse kick to the ribs, launched a millisecond after the referee's bark of 'Hajime! (Begin!),' had left me flattened, breathless, and endowed with fresh insights into the importance of seizing the initiative and thus control of a situation."
Practicing exactly what's being preached - pretty rare.