When you knit an item (socks or anything else) with natural fibers, it often enhances the look of the item when you "block" it. You first soak the item in cold water and some sort of wool wash that gently cleans the wool and evens out the stitches. After blocking, the stitches just seem to have a better look- nice and even. After soaking the item, you gently roll it in a towel to remove some of the moisture, then shape it and allow it to dry. If you make a lace scarf, or shawl, or a sweater, you lay it out in the exact shape you want it to end up- sometimes even pinning it into submission. Then you leave it alone until it's perfectly dry and it will remain in that shape. Socks can be laid out on a towel. But the easiest way to block socks into the perfect shape is to just pop them onto a pair of sock blockers and hang them up to dry. You end up with 2 socks that are the same size (assume you knitted them correctly). For socks, a lot of people just block them on real feet, but you really have to block shawls and sweaters and things like that.
Now- I realize that many of you have your jaw hanging right now- amazed that someone would hand wash and block socks every day. It really isn't that hard- and I don't do it all the time. If you use "superwash" yarn, the socks can be thrown in the washer. But if you use many natural fibers, the socks usually hold up longer if they are hand washed. If you go to all that trouble knitting them, you usually don't mind hand washing. Generally, I wash a pile of socks at one time and just lay them on a big towel on top of my dryer. It only takes me a few minutes every few weeks.
But the other handy use for sock blockers is for taking photos. They look nice and show the pattern well.
Rosa- you made my day. Your comment tickled my funny bone and gave me a big laugh. I can't get the vision out of my mind- you thinking that I have a closet full of socks hanging up. No- I don't hang my underwear up, either!
Have a great weekend, all. I'm off to work in the yard!