A couple of years ago I first ran across Crossloop, a free and easy-to-use PC screen sharing tool. I liked it so much I wrote up a review, and ended up spending a lot of time talking with and eventually meeting Mrinal Desai, the man with the vision behind the product.
Technically there's a lot that attracted me to the application. They've done a great job of simplifying the user experience to the bare minimum, rather than overwhelming them with the space shuttle control panel like most previous sharing tools. They also run their business with a heavy focus on user statistics, so they can tell you exactly how many minutes have been spent on Crossloop, 31 million at the last count with 600,000 users!
Another thing I liked was that they always had a business model in mind that wasn't advertising. Today they've finally gone live with their help marketplace. This allows people in search of technical help to connect with someone who can give them a hand. It's initially free, but the plan is to charge a fee to thos who need help, and pass that on to the helpers. This makes a lot of sense to me, there's a big pool of people out there with time and technical know-how who can answer questions, and a lot of people with simple computer problems who'd be willing to pay a small amount for help. If the system takes off, the world will end up with a lot of poor but tech-savvy folks (eg students) having a new income, and a lot of users with problems solved. There's already a lot of companies using Crossloop for technical support, this seems a good way to make it easy for individuals to get involved, rather like eBay for services.