Many public databases are already extensively linked so that complementary information in another database is easily accessible; for example, Genbank and the PDB are closely intertwined. However, specialized tools organized and hosted by specific research groups can be difficult to integrate into this linkage effort because they are narrowly focused, are frequently modified, or use custom versions of common file formats. Advantages of sequence profiling tools include the ability to use multiple of these specialized tools in a single query and present the output with a common interface, the ability to direct the output of one set of tools or database searches into the input of another, and the capacity to disseminate hosting and compilation obligations to a network of research groups and institutions rather than a single centralized repository.