The innovative nature of the work, however, brings with it a host of new difficulties not faced by traditional encyclopedias. It is increasingly impractical, for instance, to have editorial staff manually manage cross-references, tables of contents, search keywords, and other metacontent due to the asynchronous submission and revision of articles. There is also a pressure to minimize the editorial burden placed on volunteer contributors, who cannot be expected to constantly monitor the massive, ever-changing contents of the SEP and update metadata themselves.