The bulk of the opening game (lvl 1-10) is pretty much played solo and an 'experienced' player (really, anyone who is working on an alt) can run through the opening in a couple hours. So there is likely to be little or no real contact in those locations and at those levels.
I'm not suggesting that you race through the opening - in fact you should really take your time your first time through each racial beginning. They are richly detailed and a lot of fun. I recommend starting a character of each race (elf, dwarf, hobbit & man) just so you can go through the unique opening in each racial locale.
In any event, you should start to see more people once you reach the larger areas of the world. Bree for example is usually teeming with people moving about their business. And of course, I always see lots of folks in Evendim, Estelden & Rivendell.
As far as general population, the game is doing very well and is continuing to grow, but we will probably see a huge growth spurt when the 1st expansion is released around Christmas time.
I had a couple characters on Nimrod about a year ago but I abandoned them (and the server) in favor of Meneldor which is the home of TINFS - "There Is No Fifth Star" (the un-official kinship of Allah's).