http://www.cpapracticeadvisor.com/news/11542589/10-common-nexus-creating-activities-for-sales-and-use-tax
Good list - but I don't think I've ever seen such an assault on the eyes as this web site (at least for a tax website. More than half of the screen real estate is covered with ads and other internal links with...interesting...colors and fonts. But if you look hard, you can find the article. Yikes!