Yes, but it's very slow and will drain the users' battery. If you only have mobile users, it's usually not worth it to implement Coinhive.
Sorry, no. We don't offer higher shares to any of our users. We want to compete with our technical expertise, transparency and reliability, not with price.
Please also keep in mind that you get a flat fee for each hash mined, ignoring the luck involved in finding blocks in the Monero network. Our own, actual margin is significantly lower than 30%. In fact, there have been days where we operated at a loss, even ignoring our server and traffic costs.
So please understand that our rate needs to be higher than what you may be used to from other pools. We're in it for the long run.
We currently pay 0.000035 XMR per 1Million hashes. If you have 1 Million visits a month, assume a user makes 30 hashes/s (mid range laptop) and remains on your site for 5 minutes:
(1000000 visits per month * 30 hashes/s * 5 minutes * 60 seconds)/1000000 * 0.000035 xmr = 0.315 xmr / month.
Payouts happen automatically every two hours. If you have reached the minimum payout (configurable in the settings) all your pending balance will be payed with the next batch.
Payouts of at least 0.5 XMR made to plain Monero addresses do not incur a fee. For payouts below 0.5 XMR or payouts made to integrated addresses, such as used by exchanges and various web wallets, we charge a fee of 0.005 XMR per payout.
Unfortunately the transaction fees that we have to pay in the Monero network are quite high. Making lots of small payments is therefore quite expensive. Similarly, payouts sent to integrated addresses cannot be batched with other payouts into a single transaction and thus also cost a lot.
We're giving our users the option to pay part of these fees if they want to receive small payouts or payouts to exchanges.
Payouts to plain Monero addresses of at least 0.5 XMR will remain to be free.
The payout per 1 million hashes is re-calculated every few hours, based on the network difficulty and the average reward per mined block. The payout rate is strictly bound to the current global Monero network parameters. The exact formula that we use to calculate the payout is:
(<solved_hashes>/<global_difficulty>) * <block_reward> * 0.7
The difficulty is the number of hashes you have to test (on average), until you find a valid one. As the USD price for Monero has increased quite a bit lately, more and more miners participate in the network. The network tries to keep the time between blocks at 2 minutes. So if the total hashrate of the network rises, the network adjusts by raising the difficulty as well.
The Monero network is also programmed to lower the reward for each block found over time. So each new block will give a lower reward than the last one.
Currently, the price rise of Monero offsets both of these factors. Our payout, calculated in USD, is now actually a bit higher than it was when we started Coinhive.
Please read the documentation.
GPU mining in the Browser is not feasible at this point. Browsers still don't have an API to directly access the GPUs compute functions.
Of course you can emulate these compute functions in WebGL graphics shaders, but crypto requires a lot of integer operations which are a pain to implement with floats in WebGL. It could be done, but it will likely be very slow.