I think the idea is good.

Especially the ads turned into dividends thing. Even bits will usually help to payout people and investors are checking every now and then the site, so ads would be triggered occasionally.

Well I would suggest fixing one thing. The number of people earning. It's not 10%. Most likely a bug of sorts.
Also it would be fairly more interesting if less positions were earning at any given time, than still opening a new ones. There should be a limit to this, or You will end up opening new positions, lowering income for the previous ones and not really paying anyone. My 2cents.
This would at least speed up the game if nothing else.

The reinvestment is not really helpful at all. It's just a different name for withdrawal button for some of us. You will just exit the Earning queue and get on the last spot of the Open queue. So in effect investor will get nothing, just repost his/her money saving on the transfer fees. There is no other benefit. Most people do reinvest anyway. yes it takes time, but we really don't have problem that are reinvesting.

For investors, I would suggest to invest once all You wish to invest and not put a 2BTC investment there in 4 or more chunks. It serves no real purpose. You just (at this time) open more earning position just by creating more investments than is really needed. Imagine someone putting in 1BTC in 0.1 shares. It will open two positions and then try to distribute 1BTC while it could distribute the same BTC to 2 less people meaning the earning would be faster. Not to mention You spend more on fees.