If there's a theme to this nostalgia, it's that people particularly fell in love with products that helped them manage their personal information -- projects, appointments, contacts, and so on. Ecco combined an outliner with a tagging feature that would eventually be familiar to users of Getting Things Done software or Evernote. You could make up any category tag you needed and then apply it to the entries on your list, which could include Web pages and text. You also could clip things to Ecco from other programs. It's still available from compusol.org/ecco -- but it's the 1997 version.