I have participated in many retrospectives. And I have seen teams using many tools for collecting and sharing data during the retrospectives. To name a few: whiteboard with text (written by mainly one person), whiteboard with many post-its, shared online text document (like Google Doc or Google Excel), shared online canvas (Google Drawing, IdeaBoardz, Mural.ly ).
Open canvases, with the ability to write draw and add colorful notes. No more, no less. This is what I need for a retrospective tool.
My favorite (if everyone is in the same room): a big whiteboard, markers and colorful post-it.
My favorite (distributed teams’ retrospective): Google Drawing: a big online whiteboard, with text boxes and colorful boxes (simple figures such as squares and circles) .
People are intrinsically creative! Give them a few basic tools and they will express themselves. Give them restrictive tools, and you will collect fewer, less interesting results.
Below is an example of people creativity while participating on a DAKI retrospective activity.