What is the minimum for participation in the pre-sale?
The minimum is set at 10 Eth! There is a feeling that the creators of the project want to weed out small investors) but this is just the pre-sale.
During a presale it sounds normal to ask for 10 ETH as minimum investment. You don't want to deal with thousands of investors during the presale. Usually you want to pick strong strategical investors to get started.
I agree with what you said mate, a lot of ico that turned out to be successful had the same marketing strategy. They are trying to filter their investors, they're trying to choose the investors that's really in it for the project and are taking their project seriously. Actually 10 eth is a huge amount of money to invest in, so those who are investing are the ones that truly believe on the future of this project. The presale usually offers the largest number of bonuses so it's just reasonable that the minimum amount to invest is also huge. Small investors can always participate in the public sale, but I'm just not sure if they will offer any bonuses anyway with the potential that this project has, there's no doubt that everyone who invests during the ico will be profitable.
But if you compare it with other projects, you can see that 10 Ethereum is not much. A lot of people can invest that amount.