Add date to MKAnnotation title property-Collection of common programming errors

NSString’s +stringWithFormat returns an autoreleased object-since nothing else is taking ownership of it, your title is getting deallocated at the end of the run-loop cycle. You need to call retain on the new value of title, like this:

title = [[NSString stringWithFormat:@"%@ %@", t, [dateFormatter stringFromDate:today]] retain];

or, alternatively, set it to a newly-allocated instance (hence not an autoreleased one), like this:

title = [[NSString alloc] initWithFormat:@"%@ %@", t, [dateFormatter stringFromDate:today]];