I daytraded altcoins, but stopped that, as Bitcoin went up. Daytrading is a bit like gambling. Better invest on longterm. Many Altcoins went up within a few months. Ethereum was this year on 40$. Doge where in February on 0.0002 $, as I remember. Also good ICOs can have profitable longterm profits. Now I make my portfolio and hold it because I think, good altcoins will continue their upturn for years.

Depending on kind and stage of your project and if you published already parts of it, you could maybe have natural rights. F.e. someone has written a book or is photo editor , he has in several countries natural rights, if he can proove, that its his work and he was the first creator. Dont know, how it is on digital projects or ideas, but maybe a research would be it for your project, if you already published parts. If you only had an idea, make it like preposters stated, give up or make better as competitors.

Yes, as soon as they are listed on exchangers like bittrex, yobit, novaexchange or livecoin, you can trade them after ico period.
Refund mostly is not garanted. You just can trade them for the price, that buyers are willing to pay.

Maybe there could be an opportunity to lower the risked amount and play with high risk limited martingale
Ok, with bitcoin it would be difficult when not impossible.
Lets take an example with dogecoin.
Amount: 1000 doge
Bet minimum 0.00000010
Base bet: 0.00000010
Limited to 10 doge bet
Risk 17 %
If win: return to base bet
If loose: Triple (base bet x 3)

Also, if it would be not supported, governments bans wouldn't have effects to bitcoin holders. Bitcoin is a decentralized currency and can't be taken under supervision by governments. As preposter already stated, bitcoin itself has nothing to do with activities like gambling. It is just a currency. Governments will more support Bitcoin as banning it, because they take huge profits from taxes and bitcoin technology.

I know that the martingale system could only win if an infinite amount is available and an infinitely high amount is likely to be placed and Casinos are protected against martingale.
Nevertheless, it would be interesting for theory to calculate the amount in relation to the highest known loss sequence.
Example:
Game: Dice Game
Minimum bet: 1 Satoshi
Maximum bet: no limit.
Highest known loss sequence on dice game: ?

Necessary maximum amount for theoretical safe gain: ?

Paypal is good as payment method and bitcoin as investment. But soon paypal could get bitcoin as concurrent, when lightning network is full implemented and accepted worldwide.Then I would also prefer bitcoin as payment method.

Interessant.  Vielen Dank für den Tipp.

Na, wenn das so ist, dann hoffe ich mal, dass der Bitcoin nicht weiter steigt

Ja, die Meldepflicht wäre mir gleich, versteuere sowieso, nur habe ich das auch gehört mit gesperrten Konten. Aber es wird doch mehr Leute geben, die irgendwie ihre Bitcoins in größeren Mengen auszahlen lassen.

I think, you can't restore your wallet without paraphrase. So it should make sense to try to remember the passphrase. Maybe this wordlist could help you to remember the words order.
https://github.com/bitcoin/bips/blob/master/bip-0039/english.txt

I used blockchain wallet on android and only had pin. Tried just out once more. But, before I could access the wallet, they offered me to make a backup and therefore  a password is needed. Maybe your friends should only create a new password or bypass the backup or forgot that they backupped already. or its a bug.They should in any case contact blockchain wallet support. Or its the same sh... like with the icloud mails that only can be accessed  on mobile device when 2fa is created without warning.

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No, it is opposite   They mine BTC and exchange to altcoins or ghs, if choosed.
You could look to one year contracts at the miners that are already posted here. One year contracts mostly don't take fees, so ROI could be already after 6 months. But the conditions also for those contracts are: company must exist also after one year. Mining power should not be lowered and cryptocurrency should not crash down.

Yes and it looks like withdrawels are provided manually. Maybe they have technical or financial problems?

Unfortunately there are many "scam" accusations without trying to contact the support of a service or read their rules. .But good, that experienced users clarified the possible issue. Many exchangers ( or even most) have limit conditions. One even doen't allow in their tos to use it as wallet and save coins without traading for a longer period.

On the terms of use site you can find the credentials of poloniex. Maybe you find with these informations also a service phone number.
https://poloniex.com/terms/

LTC had a stable upturn since march. It was worth around 7$ this year (or even less?) and stopped at forteeth as bitcoin shoot through hardfork, so I think, LTC will stay stable on around 40 and then raise again.

Maybe ledger HW.1 could be, what you look for. With 23$ the cheapest, I found. Have no experience with it but has good raitings.

Nicht, dass ich annähernd schon soweit wäre, aber für den Fall, dass der Bitcoin so weitermacht wäre es gut, zu wissen, wie Banken mit hohen Einzahlungen umgehen.
Meine Sorge ist, dass, wenn man größere Summen von Bitcoin in Euro einwechselt (wo, wäre nebenbei auch noch interessant ), die jeweilige Bank das Konto einfach einfriert.

I'm quite sure that many governments want to replace paper money with digital currencies. Bigglobal players from fincancial sectors are already working on their own cryptocurrencies. But if we would want paper money, we would have it with paperwallets, mindwallets or physical bitcoins (   https://bitcointalk.org/index.php?topic=2080338.msg20792286#msg20792286 )      . So we are also weaponed for internet crash.