Many many years ago (maybe middle 2000's), while working for a company (Flickr competitor) that has customised a Gallery (an open source PHP photo album online)

Many many years ago (maybe middle 2000's), while working for a company (Flickr competitor) that has customised a Gallery (an open source PHP photo album online). The version we forked doesn't use db, rather a file to keep track of each gallery at the root of the folder. So technically I told my boss that it is infinitely scalable. However it is really difficult to search and run reports on these databaseless Gallery nodes. Database a long with word processing and spreadsheets are one these early days 'killer apps' that reflected the usefulness of that type of computing usage for humans.