7. The method of claim 4 , wherein determining whether the electronic message conversation data structure is missing information pertaining to the prior electronic message comprises: determining whether the electronic message conversation data structure is missing information pertaining to an electronic message that was sent by the particular participant having a sequence indicator that immediately precedes the particular sequence indicator of the received electronic message.
8. The method of claim 7 , further comprising: receiving a response to the request electronic message, the response including the prior electronic message that was requested in the request electronic message; obtaining a set of information pertaining to the prior electronic message, wherein the set of information pertaining to the prior electronic message comprises: (1) an indication that the prior electronic message was sent by the particular participant; and (2) a previous sequence indicator that immediately precedes the particular sequence indicator of the received electronic message; accessing the electronic message conversation data structure; updating the electronic message conversation data structure to include the set of information pertaining to the prior electronic message; determining whether the electronic message conversation data structure is missing information pertaining to an earlier electronic message that was sent by the particular participant having a sequence indicator that immediately precedes the previous sequence indicator of the prior electronic message; and in response to a determination that the electronic message conversation data structure is missing information pertaining to an earlier electronic message that was sent by the particular participant having the sequence indicator that immediately precedes the previous sequence indicator of the prior electronic message, sending another request electronic message to one or more participants of the electronic message conversation to request that the earlier electronic message be sent again.