Is my iCal hacked? See the screenshot.

While exporting end importing my calendar from Ical to Google Calendar on my MacBook Pro, I have noticed this, see screenshot. The exported file's author seems to be not only me (personal account email "Stefano at ...... "), but also this email "ma*****com", I do not know any "Marc".

It is probably a false alarm due my ignorance on some basics about how iCal works, but want to double check here... On top of asking around.

Thanks :-)

[Edited by Moderator]