What it is: The next evolution of tags, those little keywords that help categorize what topic a photo or blog is about, "clouds" are groupings of keywords fashioned from a variety of font sizes, styles and colors to help authors visually highlight what ideas, thoughts, concepts and products are important or hot. The concept, which is popping up on many websites -- especially news sites and blogs -- has other names, including topic clouds, weighted lists and zeitgeists
How it works: When users click on a word in the cloud, they're given a list of related items, similar to a search result. So clicking on the word Microsoft in a Technorati tag cloud, for instance, gives users a list and short excerpts of recent conversations about Microsoft.
Who's using it: While tag clouds have been used for years on sites such as Flickr and Technorati, mainstream media have adopted them of late. Washingtonpost.com, for example, features a tag cloud called "Buzz Map" as part of its online opinion section. The 10 most popular opinion topics are listed, their prominence based on how many blogs have linked to it.
Why you should care: More recently, ZoomTags (owned by ZoomCloud parent ZoomGroups) and 1000Tags are working together to try to use clouds for advertising, calling it "tagvertising" or paid tag clouds. The idea is that commercial clouds allow advertisers to buy words in a tag cloud. So when a user clicks on the word in an advertising tag, they see an ad message from the company that bought the space. ZoomTags gives advertisers a payment choice: pay-per-click (10 cents per unique click) or a billboard tag at a flat $20 per month rate. Tagvertizing is a far more appealing visual than plain old contextualized boxed advertising. And if the concept takes off, count on big boys like Google to create their own versions of ad clouds.