All searches must be done by typing keywords into a search box. Meta-searchers are fast and provide a quick overview on a topic or unique search term. A Subject Directory is an organized index of subject categories which allows users to browse through lists of web sites by subject. A Subject Directory is compiled and maintained by human beings into indexes, arranged by topic, that users can browse. There are search boxes in many subject directories, but they usually search only for sites in that particular directory.
Attachments can be documents, photographs, graphics, etc.