this site is fun and VERY educational. It teaches younger kids about shapes, rymes, letter, colors, sizes, and how to use your brain to figure out fun puzzles and games. I would highly recomend this site to kids ages 3-6.
My twin sons have loved the PBS Kids website since they were 3 years old (they are now 5). They enjoy playing the games and I enjoy that I don't need to read instructions aloud every time a new page loads (most games tend to have a character voice telling the viewer how to play a game). The characters on the games are familiar to my sons, as they are from shows on PBS Kids that they enjoy.
We have made PBSKids.org the home page on our kids' computer, in large part because this site is not covered with advertisements to toy stores or non-site vendors, unlike other kids-centric sites.
My son loves the pbskids.org website (plus we watch a lot of PBS shows since we don't have cable tv). He has been able to play them for a while now, since before he could read at all. The games are easy to figure out for a child who is good with the computer. While I never leave him alone on the computer at all, this site is great for being able to be on the other side of the room, at least -- no large ads, no distractions along the sides and bottom of the screen.. the two biggest annoyances with this website is that PBS kids PLAY is featured and you have to pay for it, so he complains about it (we did the trial and it was fun, but not worth the $$ considering how much phone apps cost). Also, the music on the games is usually annoying - and you can't turn it off. If he needs to pause his game or leave it for a while, you cannot turn off the sound w/out turning your computer volume off. So he has to finish his game before he quits so that i can use the computer later. Otherwise, a great educational website for preschool and up!