Robin Good: BigMarker is a web-based team collaboration and videoconferencing service which allows real-time web presentations, audio conferencing, project management and file sharing tools.
BigMarker supports PowerPoints, Word documents, Excel spreadsheets, PDF files, or image files and once uploaded converts them all to PDFs.
BigMarker has a potential capacity of up to 100 participants in a video event and all live meetings can also be recorded.
Pro Communities, available only for paid accounts, enable you to host public or private conferences, discussions,and files, manage projects and tasks, and organize into sub-Communities.
Free version available.
Try it out now: https://www.bigmarker.com/