If you are looking for a growing niche for a new Adsense site, then how about the baby furniture sector?  We all know that new parents, and the extended family, cannot resist spending on all sorts of paraphernalia for a newborn, such as pretty baby cribs and clothes, of course.  Over here in the UK the birth rate is rising for the first time in more than two decades so this could be a very good time to check out the possibilities of marketing to parents, grandparents and of course the children themselves a few years down the line.  There are so many items that can be bought by young families and they will spend extravagantly on their children instead of themselves.  Definitley worth checking out.