A cryptocurrency wallet is a digital place for your coins to be stored. Each coin has a certain wallet provider. That could be official GUI-wallets, web wallets and other applications. The wallet address represents a randomly generated combination of digits and letters. CoinSwitch doesn’t provide wallet addresses and never stores user deposits. To exchange cryptocurrencies, you need to have a cryptocurrency wallet address.
When issuing a transaction in IOTA, you validate 2 previous transactions. This means you no longer outsource validation to miners which requires wasteful amounts of computing power and usually a large stake of coins. These required resources are, in effect, centralizing the currencies which many believe were created to be decentralized in the first place.  
Siacoin was created by Luke Champine and David Vorick of Nebulous Inc. The Saicoin team chose not to hold an ICO. Instead, Siacoin came to life when its genesis block was mined. Even without an ICO, the Sia team managed to raise over $1.25 million in funding through investors such as Fenbushi Capital, Raptor Group, Procyon Ventures, along with angel investors like Xiaolai Li.
1) Controlled supply: Most cryptocurrencies limit the supply of the tokens. In Bitcoin, the supply decreases in time and will reach its final number sometime around the year 2140. All cryptocurrencies control the supply of the token by a schedule written in the code. This means the monetary supply of a cryptocurrency in every given moment in the future can roughly be calculated today. There is no surprise.
The term altcoin has various similar definitions. Stephanie Yang of The Wall Street Journal defined altcoins as "alternative digital currencies,"[20] while Paul Vigna, also of The Wall Street Journal, described altcoins as alternative versions of bitcoin.[21] Aaron Hankins of the MarketWatch refers to any cryptocurrencies other than bitcoin as altcoins.[22]