Here is a great article by the Wall Street Journal about SharePoint adoption and scenarios where people are using it beyond corporations. Access 2007 made a big investment in working better with SharePoint. I recently blogged about Cool as Ice and Alan Cossey who built a solution on Office Live (which is built on SharePoint) to solve similar problems from a small business perspective. Here is my favorite quote:

To date, largely unheralded, Microsoft has sold 85 million licenses to the enhanced version of SharePoint across 17,000 companies. No marketing campaigns are in the works. "When we get SharePoint in there, it sells itself," says Jeff Teper, vice president of Microsoft's SharePoint Server group.

 http://online.wsj.com/article/SB117737738757279866.html?mod=mm_main_promo_left