I've never heard of this before but it sounds interesting. I'm teaching an extra class (without a co t) of 3rd grade Elm students this year and i'm told I could have as many as 15 so this might be just what I need. 

I can see this type of system being quite effective for younger students as long as you are diligent about keeping up with it (and the prizes are good). 

I was playing around with the site last night and you can sync your phone and the computer so that when you update it on your phone it changes on the computer automatically as well.  So if you keep the page open on the projector than all the students will still see it when you update through your phone.  So if your Dojo master doesn't work out the program does make it easy to update their points without breaking your normal routine. 

I'm planning on trying it out with my extra class this semester and if it goes over well maybe i'll talk to my co teachers about integrating it into normal class as well.  Management is always an issue for me and my co teacher of the 3rd and 4th grade so this might really help if I can stick with it.

I'm with troglodyte, I try to avoid using candy or gifts as the incentive because once you start you can't stop.  Thankfully my students (even the older ones) are pretty motivated by smaller things like being the first group to line up at the end of class so I don't need to resort to candy to get them to participate. 

I'm using this program for my extra class (not sure how many students yet but I am told 15 or less) and I pretty much have free rein over how my class is structured which is wonderful. 

My reward plan is like this:
10 pt Change Avatar
20 pt Pick English book or fun worksheet for next class (I have a selection of books in my classroom and there is a good selection in my school's library and I like to do lots of crossword puzzles, decoder puzzles, mazes, hidden pictures ect)
30 pt Select a game for next class
40 pt Signed certificate to take home to their parents

http://www.certificatestreet.com/templates/blank.html

My class is 3rd grade elementary which I have three times a week and I plan to emphasize positive points rather than negative.  So I figure that most students will hit 10 points each week and therefore will all get the maximum points once (very easily twice) during the 8 week class. I usually plan for 20 minutes of book work and 20 minutes of games/books/activities each class period so it shouldn't be a problem to work in their choices even if multiple students hit their points on the same day. 

I've just started using it and I think it's great. It works really well for my youngest kids (I teach at an elementary academy), but the older ones enjoy it too. I find it's especially effective at getting more kids to want to participate. I gave them incentives for each 5-10 point increment, such as a small piece of candy, getting to change their monster, cool pencil or eraser, etc.

Thanks for the tip. It is useful, as they say! 

I used it last year as well.  For the smaller after school classes each individual had their own avatar and for my bigger classes (20 students and up) there were groups of four each with their own avatar. 
It works great, especially for younger kids who are really into making the teacher proud of them.  The older kids stopped caring as much after about two months (except for the really good students, but they aren't a problem no matter what system I use).
The biggest thing is being consistent, with both pluses and minuses.  It's good because it has the ability to offer immediate feedback on their behavior, which is the best way to encourage or discourage certain actions, but when you are using the computer/tv/projector for other activities they don't necessarily feel the immediate impact of their actions, somewhat lessening the effect.  How did other teachers get around that?

I chanced across this last year as well when I was browsing through Chrome's app store.  I wanted to do it but like someone said earlier I thought the effect would be minimal if I kept on having to switch between the screen and what I was doing on the computer.  But then the smart phone app came out! So I've started it this year.  The positive and negative sound alone tends to get their attention.  I have no long term point system but I hinted that there might be.  Simply receiving or losing points seems to be enough for my high school boys and I have other deterrents to back up the negative points for sleeping and being late. Some of the first years have made student accounts.  I was doing random student selections in class before with random.org but this way is much better.  The co-teachers love it too but I haven't seen any of them try and adopt it.

I've been using Class Dojo for my extra-curricular class in the morning.

The class has around 20 3rd and 4th graders who were pretty rowdy (some of them, anyway) to begin with, but have calmed down a lot since I've started using this website.

I found that I was using too much time to track down the kids on the app to give them +/- points in real time, so I've started giving out laminated dollar bills for good behaviour/work. At the end of the lesson I get the Ss to line up and review some vocab/expressions and then tally up their dollars for points. It's been working really well so far, kids are really stoked for getting more 'money' and like to see their app points rocket up.

I'm planning on giving monthly awards of candy or pencils etc to the top 3 students, then reset the points for the new month.

I like this. I'm trying to get away from using candy, especially with the older kids, because I'm sick of my students crying/whining/coming to blows when someone earns a candy and they don't.

Has anyone used this in a class of 25+ students?

I use class dojo for 850+ middle school students and I also swear by it.
Before I introduced it my students never volunteered or had any real motivation. After, there was competition and almost aggressive levels of volunteering.
Each class has 35-40 students. I have a mandatory seating assignment by class number so I can reference students quickly and get them points faster.

I leave their points up on the smartboard at the beginning of class as a reminder and motivation. I find if I don't let them see their points often then they forget/don't care.  I think my students are far more interested in their own score as well as who has the highest points. I don't think very many students have laughed or even noticed the fact that some students just don't have any points. Unless a student has negative points which is only in a couple classes.

If anything it's created some really healthy competition between classes. If a class can get 400 points by midterms we can watch a movie or have a little party. So I post class points up permanently on the side of the room. They're extremely interested in class points and I had class 1-4 and 1-6 battling it out over who could have the most points (there isn't even a reward for this).

I introduced it in the middle of the year and found it worked a lot better than stamp system. Stamps were ridiculous for me because I had to walk around and thy would forget their books or what have you. It wasted class time.

Rewards:

+10 points = change your avatar (I leave it as a default monster but at 10 points they can change it to Exo, Larva, LoL characters, etc).
+20 points = 1 piece of candy.
+30 points = prize box (it has chocopies and kicker bars in it).
For every 10 points in Dojo they earn they get +1 green mileage point. Just give a friendly co-teacher or their homeroom teacher a list of who gets green mileage.

Punishments
-5 points = sit with the teacher and -2 green mileage points
-10 points = clean the entire classroom alone. - 2 more green mileage
Neither has ever happened.


1st grade loves it.
2nd grade was into it but I only see them every other week so it's hard to say what a full year would have done. Maybe burned out, maybe kept them enthused. I really can't say.
3rd grade couldn't really be bothered but they really liked the green mileage aspect of it (for getting into high school).

If you have wifi you can put the app on your phone or coteacher's phones and everyone can give points remotely.

one thing i would suggest when using class dojo for large classes, is to allocate points according to teams rather than individual students.

so in the class dojo program itself, each 'student' would actually be a team, and each team can win or lose points according to whatever behaviours you set. for example, if you have 6 teams in Grade 4-8 (or whatever), you would have 6 'students' in the class dojo program. it makes it FAR more manageable, and the students within each team will also help to police each other.

don't forget there's also a great smartphone app for class dojo that lets you add or subtract points on there, so you don't even need to be in front of the computer. you can just walk around, monitor the students, and add or subtract points on your smartphone according to whether or not they're doing their work, if they're misbehaving/behaving well, etc.