Mail Search: It's Getting Personal!

Web Mail has significantly changed in the last decade. It keeps growing with 90% of its traffic being generated by automated scripts or \"machines\", [1]. At the same time, major mail services offer more and more free storage, ranging from 15GB for Gmail and Outlook.com to 1TB for Yahoo mail. As a result, we keep accumulating messages in our inbox, rarely deleting (and sometimes not even opening) many, [2]. Our inbox has become a big store mixing important information, such as e-tickets or bills, together with newsletters or promotions, from which we forgot to unsubscribe. Search is therefore a critical mechanism in order to retrieve the specific messages we need. Unfortunately, search in mail is far from being as trusted (and used) as in the Web today. Everything is personal and often private, from the content of the mailbox, to the search strategies, users' needs and queries, thus making traditional Web search techniques inapplicable \"as is\". Failure is evident when we can't find a message that we remember having read, and this increases our frustration. Most mail search services return sorted-by-time results in order for us to scan results chronologically and increase our perception of perfect recall. At the same time, the ranking mechanism drops less relevant results, in order to prevent them from being ranked first if recent. So in order to increase a (false) perception of recall, these systems actually hurt recall! Ranking results by mail-specific relevance would actually increase search success, [3] yet it is not widely adopted, with the exceptions of Inbox by Gmail and Yahoo Mail that show a few relevant results on top of traditional ranked-by-time results [4]. In addition, many of us still struggle with expressing our needs, typically issuing very short queries, like in the early days of the Web [5]. In this talk, I will first highlight the key characteristics of mail search and how they differ from Web search, in terms of searchers' needs and behavior [2,5]. I will then present recent progress in mail ranking [3,4] as well as in query assistance tools [5,6]. Finally, I will discuss directions for future research, and the need to revisit mail search and invent search mechanisms specifically tailored to the personal data store that our inbox has become.