MCCLATCHY NEWSPAPERS -- July 16 -- Seniors today are the fastest-growing users of Internet dating services and the fastest growing group of cohabiters. Longer healthy life expectancy is part of the explanation. According to Mark Brooks, a consultant who tracks the Internet-dating industry, the number of seniors joining online dating services has risen at double-digit rates annually since 2003, the most of any age group. But attitude changes are probably the biggest factor in the expanding social lives of seniors. Falling in love at an elderly age was seen as somewhere between unwise and dementia.