Even if you buy TH/s of hash rates, you will not have ROI. Although you don't have to worry about electrical cost, the maintenance fees and price per GH is ridiculously high. Don't even think about mining unless you buy a lot of ASIC (not preordering)  and have nearly free electrical cost. Cloud mining will not be profitable with the increasing difficulty and maintenance fees.

The code just generates a voucher code with the money you specify and allows another user to redeem them if they have the code. Just exchange them back to BTC and withdraw them to your own wallet address. The minimum withdrawal for BTC is only 0.002 which you can easily get more than that.

The amount of time needed for the transaction to be dropped depends on the client you use. Some broadcast it forever while some drop it after a while. It will eventually be confirmed if it is broadcasted for a long time but it does take a lot of time. Minimum fee is 0.0001 unless the input is old enough plus the input and output is at least 0.01 and above.

Bitcoin core downloads the entire blockchain and allows you to use features like BitcoinRPC but Multibit connects to their server for the blockchain and checks your balance there and don't allow RPC features. You have to trust MultiBit servers to have valid information for your wallets. Bitcoin Core does not need to have trust since it finds the longest valid chain from a couple of nodes.

How much ram do you have? Whats your system specs? 32bits or 64bits. bad_alloc means that you do not have enough memory available. What's your dbcache value?

It depends on the pool's policy, if they decide to discard transaction with no fees, your transaction will not be confirmed. The older and bigger amount your coins is, the more priority the transaction gets. I used to do this all the time but it does take a lot of time to do so. Usually, I see Bitminter confirming my unconfirmed no fee transaction. I guess their fee policy isn't strict.

If any of the computers you used to access blockchain.info have malware, you would have exposed your backup copy and password to the attacker, not just on the computer you are preparing to import to. MultiBit and electrum are both opensourced which means you could easily verify the source or build it from the source.

You cannot easily reset password and if someone gets your email, they can reset the password and gain access to your account. If someone send sensitive information on the PMs, Bitcointalk automatically sends a reply of your PM to your email and the person who have access to the email can see the information. Just use a temporary email which will be deleted after an hour and will not give others the same email. If you forget your password, contact theymos and he MAY reset the password for you.

The coins have been moved after 3 hours which means that the system would most likely have been notified about your deposit and moved them to their own wallet. I believe you have entered a phishing website or their system have issues. Try contacting their support. As onion links are complicated, you may have entered a fake silk road website. Have you try to recheck your address on silkroad? There are viruses which changes your clipboard Bitcoin address to their own.

They make a signature design and ask you to put into your signature area. You have to post a number of post which are constructive in order to recieve payouts. When people browse through threads, they are likely to spend more time looking at the more constructive post and usually look at the signature too. This is a good method to introduce useful post to the community while discouraging post spammers. Compared to forum advertising which cost a few BTC and only displays your ad in rotation for one week, you can use 30BTC for 200++ people to put their signature on their signature space for one month and post constructively which is more cost effective. Since this ad change applies to every single post, those browsing older threads would see the signature also.

Anti Virus does not guarantee that you do not get infected by trojan or other virus. There are plenty of fully undetectable viruses which means they cannot be detected. The best method is to verify and build the wallet yourself from source, I wouldn't download the wallet if its not open sourced.

They are usually safe, unless the mixer is new. They can be easily traced if you do not set any delay. Use a new address for every transaction and do not post the address on the internet, your identity can be linked if you do so. Using tor can also anonymize your connections.

I agree with this fully. We often see cryptocoins on news but usually, the one getting the media's attention is Bitcoin. Alt coin is usually more volatile in price than Bitcoin. Unless there is a service which immediately exchanges your coins to fiat or Bitcoin without losing the value if the market crash, I don't see why merchants who are using Bitpay would switch to alt coins. Bitpay already accepts instant payment without confirmation for most cases.

If you have no need for Bitcoin core, not using the features available only in Bitcoin core, not planning to run a full node for long periods of time, try lightweight, SPV wallets. They offer basic features, sending and receiving Bitcoins, Multibit and electrum are one of them. If you have a need for Bitcoin core, use torrent to download the bootstrap and place the blocks to the data folder.

Look around the forum for giveaways, lend your BTC to trusted member for small interest, learn some coding and help users to code things, signature campaigns and perhaps sell exotic items available in your country. Signature campaign is recommended for those who can really contribute actively, lending BTC to people does have significant risk, just take note to request collateral and avoid lending to low rank people.

GPU mining is a history since last year October, a single USB miner can easily be faster than a world fastest GPU while consuming less power and emitting less heat. My advice is, sell those GPUs and either save them or spend them on BTC. Try as much as possible, don't buy ASICS, unless they are proven and will ship on time or you have very cheap/free electrical rates.

The real people who get the most profit is the ASIC manufacturer. They "test" their customer's orders and profit themselves. Most of the big farms are hosted in datacenter with low electrical cost and good cooling. They can easily buy some used raspberry pi as a controller, or some of the ASIC even come with a controller.

Collision is HIGHLY unlikely. In order for a collision to happen, it would take a super computer, faster than all the computers in the world combined to generate one such address in a million years. Even if you are looking for a vanity that is more than 6 letters, it is already very hard.

It really depends on your definition of online wallets. If the website have full control of your BTC (coinbase, online exchanges), you should try to minimize the use. If the website do not have control over any of your BTC (Blockchain.info), you have lesser chance of losing your BTC. Try to keep a large portion of BTC in a cold storage, small portion of it on online and desktop wallet as they usually will have lesser security.

Seperate the play money from actual BTC, crediting users 10-100 play money and allow them to test the site. If they like the features, they will naturally deposit bitcoin. This however,don't attract as much people as the one who credit real BTC and allow them to withdraw as they can test out withdrawal feature without risking any BTC.