Communication services enable users to communicate electronically using various modes of communication. Conversations between groups of users are common, where emails, other communications, and data are exchanged repeatedly over a period of time. Provision of tags in communication environments may enable the users to organize, search for, and share content of the conversations more efficiently, improving communication and collaboration among the users. For example, a tag module of a communication service may associate a communication with one or more tags such that the tags are persisted with the communication as the communication is exchanged, and transmit the communication to participants of the conversation. The tag module may also provide automatic classification, suggestion, and/or completion of the tags. The tags may be displayed in conjunction with the communication through communication user experiences associated with the participants, where the participants may interact with the tags for search and organization purposes.