Hi, sorry wasn't sure wither or not this should have been added onto the edited text post as it's been closed or just make a new one.
Like in skype (man I love using skype as an example) when somebody edits a message it is marked and identified as modified. Just wanted to add this so that people are aware that the text has changed since it was first posted ~(be it typo, or a change / update of information).
This has been released to live.
This has been implemented and will be released in the next version.
We have taken this idea on as something to be implemented for the next release.
All messages sent do have a timestamp, we just didn't want to put too much non-RP information on that page so we tried to keep it simple, however the data is stored in the system.
We will look at getting this added shortly as it will help people see if something has been edited.