Geoffery Bilder's comments about the unsuitability of URLs as long term identifiers (as opposed, say, to DOIs) came to mind when I discovered that the domain phthiraptera.org is up for sale: This domain used to be home to a wealth of resources on lice (order Phthiraptera). I discovered that ownership of the domain had expired when a bunch of links to PDFs returned by an iSpecies search for Collodennyus all bounced to the holding page