According to the study called "Quality improvement of e-mail communication in work groups and organizations by reflection", the most frequent qualitative shortcomings that recipients must face in managing the number of e-mails received were:
• Receiving multiple e-mails with the same or similar information, from different sources.
• Receiving incomplete or poorly written messages means that they will immediately receive more messages on the same subject to complete the information or to clarify it.
• In some cases it is difficult to understand to what specific activity or job the mail corresponds to.
• Receiving e-mails from unknown senders.
• Receiving e-mails where the purpose of the sender isn't clear.
• Receiving incomplete messages that require clarifications by telephone.
• Receiving messages where it is difficult to establish the importance and/or urgency.