(NSString *)timeDifference:(NSString *)fromDateString {
    NSString *diffString   =   @"";

    NSDateFormatter *dateFormatter  =   [[NSDateFormatter alloc]init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *fromDate                =   [dateFormatter dateFromString:fromDateString];
    [dateFormatter release];

    NSDate *endDate                 =   [NSDate date];
    NSCalendar *gregorian           =   [[NSCalendar alloc]initWithCalendarIdentifier:NSGregorianCalendar];
    NSUInteger unitFlags            =   NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit;

    NSDateComponents *components    = [gregorian components:unitFlags fromDate:fromDate toDate:endDate options:0];

    [gregorian release];

    NSInteger days      =   [components day];
    if (days == 0) {
        NSInteger hours =   [components hour];
        if (hours == 0) {
            NSInteger minutes   =   [components minute];
            diffString      =   [NSString stringWithFormat:@"%d minutes ago", minutes];
        } else {
            diffString  =   [NSString stringWithFormat:@"%d hours ago", hours];
        }
    }else {
        if (days == 1)
            diffString      =   [NSString stringWithFormat:@"%d day ago",days];
        else
            diffString      =   [NSString stringWithFormat:@"%d days ago",days];
    }
    return diffString;
}