Re: Extended Nursing
There s a really good summary of the benefits of extended nursing on kellymom:
http://kellymom.com/ages/older-infant/ebf-benefits/
I think a lot of us don't necessarily plan to nurse past a year (although some do); it's just something that happens. You struggle early on to make breastfeeding work and once it really starts paying off, you aren't in a hurry to give it up. For me, my baby turned one and was still very much a baby and still very much needed to nurse; so benefits aside I just rolled with it. At one point my husband said to me, "I figure if he is asking to nurse, then he still needs to nurse." 
At 13 weeks, I doubt I could have imagined nursing my son at 20 months. I had a hard enough time imagining still nursing at 14 weeks. But nursing became easier as time passed, then became enjoyable even as more time passed, and then became indispensable as yet more time passed. My son is hurt, angry, or sad - I nurse him and he's instantly content. Then there is the teething. These second year teeth have been absolutely miserable for us, and I'm not sure I could survive it without nursing. Breastmilk still contains a large portion of the nutrients that toddlers need (check the link); so I didn't need to worry that my son was slow to pick up on solids, and both my husband and I never felt that we needed to coerce him to eat. There are restrictions on how much cow's milk a child should drink (it can irritate the intestinal lining and inhibit iron absorption), but a child can drink as much breastmilk as he likes. I also liked how I no longer had any goals after a year. I was simply nursing my son because it was best for us not because the AAP states that is what is best for babies. There was something liberating in that for me.
Extended breastfeeding has been really wonderful for our family, and I wouldn't do things any other way.
K. Sophia - Mama to my little lactivore, the amazing Mr. X (11/10).