If we're talking about a blockchain fork, in simpler terms it would mean that the blockchain 'splits'.
I see a lot of thread on bitcoin fork all of sudden, just wondering what will be the affects of this split in blockchain and does a normal user who doesn't mines really need to know about what a fork really is? Someone care to explain it in simpler terms.
Well... Those questions are a bit harder to answer. It will depend on how a fork takes place. If for some reason people running a certain client are deemed to be running an incompatible blockchain then it would affect them. To avoid this as a bitcoin user all you have to do is keep up with client updates. If upgrading is crucial at some point I'm sure it'll be hard to miss.
Aside of that, there are many "ifs" about the recent revelations. If Gavin decides to publish a client that will hard fork the current blockchain, it's very much possible that for a period of time, two blockhains could be running at the same time. So while balances are the same on both at the start of the fork, it's also up to the miners. If miners/pools mine exclusively with bitcoin core/xt then one chain gets rejected. If both chains are kept alive however, earlier owners of bitocoins have coins spendable on both chains.
So it's up to each individual, you won't lose bitcoins if you're careful, but you'll have to be cautious about new updates, services you use etc.
It would be like having an altcoin called XT, that shares all your previous BTC. It's a bit of a mindfuck but that's exactly what it is. They may co-exist forever as long as some people are processing transactions. Other decentralized p2p projects have forked before, and of course one version ended up being the popular one, but the other one still exists, for example freenet.
