C~ 96 APRIL 13-~8, 1996 Email overload: exploring personal information management of ernail Steve Whittaker Candace Sidner Lotus Development Corporation One Rogers St Cambridge MA. 02142, USA +1 (617) 693 5003 +1 (617) 693 7737 [email protected] [email protected] ABSTRACT Email is one oftl~ most successful computer applicmiom yet devised. Our empin~:al ct~ta show however, that althongh email was origiraUy designed as a c~nmunica/ons application, it is now used for ~tional funaions, that it was not designed for, such as tab management and persona/ afoOt/v/rig. We call this ernt~l oveHoad We demonstrate that email overload creates problems for personal information manageaa,cnt: users eden have cluttered inboxes cor~mining hundreds of n~:age~¢, incl~rling outstanding tasks, partially read documents and conversational threads. Furthermore,, user attemt:Xs to rationalise their inbox~ by ~ing are ~Ron unsuccessful, with the consequence that important rr~ges get overlooked, or "lost" in archives. We explain how em~l over/oad/ng arises and propose technical solutions to the problem. K r.oras Email, information overload,, personal information management, asynchronous communication, ~ task management, communication, ethnography, empirical sn~es. WHY STUDY EMAIL? Email is one of the most successful computer applications yet devised. There are milhons of email users world-wide who often spend significant pmporaons of their work time using emafl. Research suggests that email has o~Luibuted to the growth of distn~ned organisations, by allowing people in different geographical areas to cornmunicate across dme and space. It has also led to the emergence of on-line communities by supporling asynchronous coaua-amication [8]. ~rmil has been the subject of many studies, including pioneering early work that focussed on the social and communicative aspects of ermil comparing its usage with face-to-face communica~n [8]. Nevertheless, there is little systematic ~ta on its usage and utility as a workplace technology. Funhermare, the success and popularity of email has led to high claily volumes of email being sent and mcoived. Reseazch has not yet ~aa~essed how people organise and manage large amounts of informatiort This study thea'r,,fore preseras a quantitative analysis of Permission to make digital/hard copies of all or part of this material for personal or classroom use is granted without fee provided that the copies are not made or distributed for profit or commercial advantage, the copy- fight notice, the title of the publication and its date appear, and notice is given that copyright is by permission of the ACM, Inc. To copy otherwise, to republish, to post on servers or to redistribute to lists, requtres specific permission and/or fee. CHI 96 Vancouver, BC Canada © 1996 ACM 0-89791-777-4/96/04..$3.50 the mailboxes of 20 users, along with 34 hours of interviews to address these new questions. Email applications were originally designed for asynchronous communicat/on, but as our analysis will show, email has evolved to a point where it is now used for multiple pml~OSes: document delivezy and archiving; work task delegation; and task tracking. It is also ttsed for storing personal names and addresses,, for sending teaadnders, asking for 0L~istance, scheduling appointments, and for handling technical support queries. We use the term eracgl overload to dee, cn'be the use of email for fi.mOions that it was not designed for. We discuss three main email functions: tax management, personal archiving and asynchronous cornmunicadortz The central question is how well a single tool can support all these functions. Subsidiary questions must also be asked in each ~egory. Task management requires users to ensare that information relating to current tasks is readily avaikTble. This both preserves task context and allows users to determine the progress of ongoing tasks. Task management also involves remindng oreself about when particular tasks or actions have to be executed [1,2,4,6]. How do people do this inemail? Personal archiving or filing addresses how people organise and categorise longer term information, so that it can later be retrieved. Archives are not of immediate relevance to current tasks, but are constmaed for reference or anticipated future use. Research shows that users exmrience major pn:t, lems in generating apprq riate folder labels when filing longer term izfftnmalion for later retrieval, and in reconstructing these labels when they engage in later retrieval [1,2,4,6]. To what extent do these problems occur in email7 Asynchronous communication is concerned with interaction in a permanent medium across space and time. Research has characterised face-to-face workplace communications as consisting of repeated brief communications [3,10l. Such interactions are seldom one=shot, and workers often engage in multiple intermittent interactions in order to complete a ~- Workers are also usually engaged in several independent, but concurrent ongoing conversations, wi~ the requi~-,ents of tracking separate conversational threads and switching contexts between conversations [ 10]. Does email communication have these characteristics, and how axe asynchronous communicaaons conducted? To provide preliminary answers to these questions, this study presents qualitative and quantitative information about the use of email for task management, personal arc, hiving and asynchronous communication. We describe the problems people experience with 276t3-18, t996 C~I] 9~ APRIL eacia of ttese ff~ions, and the strategies they invoke to address the lxd~,lem.s. Finally ~e suggest potential technical solutions. SYSTEM ~ METHOD We studied users of NotesMaiL tlx email comlxment of Lotus Notes. This diem-server system has a GUI with a number of standard features, including the abaity to compose, re#y to, copy (,~), and blind copy (bcc)messzges to other users. Inmming unread messages are delivered into the inbox (called "uncategorised" in Notes), where they appear in a different cokmr fi'om messages the user has "epened" and read. Once "opened", they appear m the standard cokJur. The system pawides users with the ability to file information: they do so by