The standard keyword search has its place, but there are advantages to varying how you and your students navigate the web. One way to search online is using tags. Tags are descriptions, often one word, created by the person who has posted content to in order to make it searchable. For example, a person posting a photo of a holiday on Flickr might tag it with the following: Istanbul, Blue Mosque and Twilight. An art teacher wishing to show an example of evening photography may find the photo while searching, as would a student searching for pictures of the Blue Mosque.
Searching by tags is especially useful when searching for images, other media or blog postings. It is also a great way to appeal to visual learners who prefer initially perusing images rather than a linear findings. Also, can be a beneficial way of guiding your students as they attempt to find meaningful results in the vastness of the web.
Take some time and try Tag Galaxy. You can access it simply by clicking on the above image.
You may also enjoy reading about Visual Bookmarking with Symbaloo.