Yes, it's true that .22's aren't very loud, and just like Matt, I thought that I could get away without wearing hearing protection while shooting. One day after about 500 rounds between me and my shooting buddy, I went home with a noticable clogged and ringing feeling in my ears. I had experienced it before but it would usually go away in a few hours. This time was different! It got a little better as time passed, but the ringing never went away. It's been a long time since I've heard complete silence. At night when I go to bed and all is quiet, I still hear a ringing sound. It's affected my hunting ability as well. Now in the spring I find it hard to hear that gobbler thats a couple hundred yards away, thats why I usually hunt with a friend. I have to rely on their ears instead of my own. And in the fall the deer seem to sneak up on me ever so easily even on the dryest of days.
Bottom line, ALWAYS USE HEARING PROTECTION WHEN YOU'RE SHOOTING!! I learned my lesson the hard way and I regret it every day. Tinnitus isn't something that you want to have to live with. There is treatment, but there is no cure.
Shoot safely and protect your hearing at ALL COSTS!