Tagging, or the bookmarking of digital photos and videos on content-sharing sites such as Flickr and YouTube, allows users to organize information and offers opportunities for quick market research. Amazon.com (AMZN

) has recently started featuring customer tags that allow its shoppers to link to other, related products. Seeing how consumers associate products can inspire hybrid product designs or cross-promotional brand campaigns. Some sites, including Flickr, technorati.com (which tracks blog usage), and the recently launched Vox (a blogging service) offer tag clouds, which are graphic visualizations of tags that are "hotter" among users, depicted with larger type. Tag clouds can provide quick snapshots of what topics, products, and trends are most popular at any given time.