A little suggestion for when you find the message, you can click on the TICK next to their avatar (picture) and then when you need to find it again you select the underlined link (above the questions in main community) and it will show you all the messages you have marked.
To find posts, that you have written: click on the underlined link that says: my questions.
>To find posts, that you have made a comment on: click on the underlined link that says: my answers.
Both of these are also found on the Community Home page underneath the Public/Personal/Private Tabs.
I hope this helps. hugns n roses, M
Hi francoise you can always try putting some of the words in the Search upper right side under Ask the Community, it might bring up something for you ...