A software that could fathom all the distances to bring the host and their audience on the same page, virtually if not physically is what can meet the above requirements. The solution is in the form of Web Conferencing Softwares, and if those are available for free then it is a boon.

A basic Web Conferencing SW which is free should at-least have screen sharing capabilities, chat facility if not complete audio conferencing facility; whiteboard and session recording and replay would make the offering even better. The feature list is exhaustive but I have focussed on these essential basic features to come up with a list of Free Web Conferencing Tools. My ordering might not match yours, I have tried to order the tools on the basis of the relevance of the features provided, the degree of freedom the tool provides, open source ones before the limited functionality paid versions.

Software	Description	Screen Sharing	Chat	Audio Conf	White Board	Record Replay
openmeetings	OpenMeetings is a free browser-based software that allows you to instantly set up a conference in the Web. You can use your microphone or webcam, share documents on a white board, share your screen or record meetings. It is available as hosted service or you download and install a package on your server with no limitations in usage or users. Free-dom OpenSource Tool
bigbluebutton	Though the software is developed for Online Learning, with the feature set it supports it can very well be used for Web Conferencing by SMB’s. Free-dom OpenSource Tool
sabameeting	With the SW users can share audio, high-definition video, and files via online web meetings with prospects and collaborate in real-time by sharing documents and applications. Users can have full control of their online web meetings with integrated audio conferencing software and more. Saba Meeting works on mobile devices for mobile web conferencing, including iPhone and iPad. Free-dom Unlimited meetings for Up to 4 Attendees and 1 Host with standard quality video and 300 MB Storage
mikogo	It is a Desktop Sharing SW(One2Many) which supports Multiple Meeting Participants, ability to switch Presenter,Remote Keyboard and Mouse Control, Session Scheduler, Profile Manager, File/Clipboard Transfer. Free-dom Free unlimited meetings for  non commercial use, meetings with up-to 2 participants.
vyew	Vyew allows you to meet and share content in real-time. It does not require any installations and is compatible PC, Mac, Linux, powerpoints, documents, images, videos, mp3's, flash files.The SW also  provides some collaboration features - continuous rooms are always saved and always-on. Contextual discussion forums, voice-notes, track and log activity. Free-dom The free version is free forever. Unlimited use with up to 10 people, Room Limit of 20. What's the catch? It's ad supported.
webhuddle	WebHuddle overcomes many of the common challenges faced by other virtual meeting applications on the market -- such as high-price to entry, compromised network security, large client downloads, and unreliability. Free-dom OpenSource Tool
anymeeting	AnyMeeting offers free and low-cost web conferencing, video conferencing and webinar services for small business, with all the features and capacity of expensive services. The SW supports YouTube Videos,  PowerPoint Slides, Twitter and Facebook Integration, Send Invites & RSVPs Personal Meeting URL and Social Profile Page Free-dom 200 Attendees, Full Featured with ad Support
join.me	Facilitates Instant screen sharing, you can get everybody on the same page, when they're not in the same room, instantly. Review documents and designs. Train staff. Demo products or just show off. join.me is a ridiculously simple screen sharing tool for meetings on the fly. The SW also allows to share control and send files. The join me viewer is available for iPad/iPhone or Android. Free-dom 250 Viewers Supported with the free version.
meetingburner.com	It is an Instant Screen Sharing SW, Mac & PC Compatible It features Mobile Attendee Support, Meeting Scheduling, Streaming Video of Host, Instantly Change Presenters, Automated Email Reminders, Facebook Promotion Tool and Registration Widget. Free-dom Host up to 10 webinar attendees for FREE with no ads - forever!
screenleap	Share your screen instantly to any device with any browser, without any downloads, installs or sign-ups. The Screenleap browser extension for Gmail allows you to start sharing your screen without leaving Gmail.  Free-dom You can use the service 2 hours/day on shared servers. You can also choose for a Personal Handle. The free service does not ensure encrypted content exchange.

Image Source [guim.co.uk]