The Marketo-WebEx-SFDC integration generally works well in terms of telling me who attended a webcast and who was a no-show. However, if you go to WebEx and download their attended/no show report, they provide more extensive data on:
How long someone stayed logged on
What their attention level was like
It would be very interesting and useful if the integration between WebEx and Marketo were enhanced to allow for use of this information in lead scoring -- for example, webcast attendees who showed a high level of attention could be scored accordingly.