>If I look at message#1599163 and the data of the poster of this message I see that the message is from 4/28/2014 and the last login of the poster is 2/21/2014
>Does that mean he was online for 2 months?

Yes, that would be it.

>Also the date format in the message header is DD/MM/YYYY to me while the member detail is MMMM DD, YYYY

I will adjust accordingly and add additional formats to support the dot.