Most of my engagements include a review of the media that will be displayed to attendees during an online event.  The most commonly used media is a powerpoint or other presentation software.  Here are a few of the BIG thoughts around presenting your slides online:

People cannot see you, your presentation online must be more visually interesting and engaging than a physical one.

Visual rules still apply!  80% of what we receive is visual; audio is less than 15%: 

Agenda

Bios and pictures - Who are you?

One point per slide

60 to 90 seconds per slide

45 to 50 minute monologue is the limit

Picture speaks 1000's

Video and TV clips are very clever and engaging

Graphs, charts, pictures, clip art, single phrases, meaningful words, and quotes are the best ways to make a point.  Words go in the speakers notes.

Verbiage in the speaker's notes (please)

Call to Action - What do you want attendees to do AFTER the presentation?

Landing page - Web page attendees view after the presentation (handy sales tool)

Contact information - web, phone #'s, address,

Collateral - downloadable presentation, articles, white papers

There are many more, but these are some of the big ones.