It may be chronological, a logical series of topics progressing from the general to the specific, or alphabetical, as in indexes, encyclopedias, and glossaries.
Straight sequences are most appropriate for training sites.
More complex sites may still be organized in a logical sequence, but each page in the main sequence may have links to one or more pages of digressions, parenthetical information or other information on other sites. Grids Procedural manuals, lists of university course, and medical case descriptions are best organized as a grid. To be successful, the individual units in a grid must share a highly uniform structure of topics and subtopics and the audience must understand the nature of the overall structure. Grids have no particular hierarchy of importance. Grids can be hard to follow unless users recognize the interrelations among categories of information.