If you log all changes to website and you use PIWIK annotations for this task, you have to manually add time to beginning of text of annotations by yourself. See attached jpg.
My suggestion is to at time of creation of annotation PIWIK proposes current date and time up to minute accuracy.
Attachment: piwik-annotation-with-date-in text-field.jpg
good idea! Especially helpful if you do more than one change a day... may help finding bugs on your website which were introduced by a change earlier this day...
Yes good idea! duplicates #4888