As a creator of http://bboskill.com
I want to explain some issues...
I can see you already have some info about it: it's not a BBO's tool, it uses BBO's MyHands and it's not perfect. And it would never be. More you think and solve one problem there'll be 2 new problems.
For now service has 3 obvious major problems:
1) Players who play with weak opponents are experts and world class
2) Really strong players who play only with friends, also strong players are advanced, intermediate or even lower than that
3) It gets only 1 month of period
1) and 2)
There is a correction based on partner's and opponent's strength. The only problem is I have really small database for now and I don't have at least one monthly result for each player. I think it would be more than rude to torture MyHands server with some scrap scripts, so I am only sending and storing requests that users make. Well, that takes time.
For correction I came up with this calculation:
(-partner+opp1+opp2)/3 for each board played (I don't think it's perfect and I need to test it). As I don't have many results they are 0,0,0 divided by 3 or 0,0,0.3 divided by 3 is only 0.1 and too many zeros lead to small correction. How would this work, time will show, but with good database correction will be big factor in calculation.
I've tried to protect top class players. They often play under 200 hands monthly and usually with friends and only several different players. If we imagine closed group of world class players, who only play with each other, someone will score under zero. There is no trick I can represent their real level and rating correctly now. Correction will do the job, but only if big part of them play with other, regular players and they score like 2.0 imp/board. So, I am making my list of famous players around the world. Some of them are on the list, some not yet. When I calculate correction against 'protected' players I take their real score if it's bigger than some my, imaginary number, and if it's lower I take that number as a score(like +1.0 and protected world class player can't go under that for calculation of corrections )
I store all requests made by users. After couple of months I'll have some timeline and rating will be more accurate. Myhands won't allow you to take longer period than 1 months and that's it. I am simply limited to work with that.
Basically I am aware of all problems, and more and deeper you think even more problems you'll find. Just think about: GIB hands, TM ("Why is my fault when my team mates go down on 6♠
where they should claim easy 12?"), "I play only MP's. Is that transformation you make to imp correct?" and many others.
I look at this site this way:
-It's made for several days with very limited resources
-It's much more popular than I expected, so it's not complete "rubbish" as many love to say
-It's great for some purposes I thought it would be mostly used: e.g. discover "world class" player in individual tournament in front of you with -2.0 imp/board or make fun of your friend because he is only advanced and you are expert (Some of my friends already told me they stopped fooling around and they are trying to play more seriously. Some of them told me they feel more competitive now. For me they all look much more like 7♦
As long as people don't get it too seriously, there is no danger.