It's very hard to know whether sidechains will help or hurt ethereum... You could put an ethereum clone in a sidechain, although there'd be downsides to this... It's hard to know how mining would work for such a chain, it would have to work differently than either bitcoin or ethereum mining ("merge mining" alone won't work due to the fact that ethereum has 50x the block rate as bitcoin) and sidechains have extra mining costs that need to be obtained somehow (such as through a "wealth tax" on unused accounts).

On the other side, ethereum itself could host bitcoin sidechains as contracts, adding value to the ethereum network.

My own best guess is that sidechains will be a net positive for ethereum adoption, but a net negative for the ethereum currency market cap.

> My own best guess is that sidechains will be a net positive for ethereum adoption, but a net negative for the ethereum currency market cap.

I don't see how adoption and market cap can go in opposite directions.

Contracts will pull in bitcoin using sidechains, but "gas" will use the ether currency. Ether market cap would decrease because the coins aren't locked down in contracts, but in active circulation.

Basically, it means you're decoupling the "store of value" and "medium of exchange" aspects of money, using bitcoin to "hold value" and ether to do the rest.

Bitcoin subreddit has +140k users, Ethereum has +3k. Despite it seeming super cool and impressive, there just isn't a significant community developing around Ethereum. And you can't make the case that Ethereum is newer as its been around longer than the Dogecoin community and that has 80K users.

I want to care about the alt-coins, especially Dogecoin, I just agree with fredwilson and @cdixon that only Bitcoin has the network effects going for it. Impressive developers being behind the sidechain concept, see e.g., blockstream.com, will only further the gap.

You've got good points, but Ethereum is older than Dogecoin in technicalities only (if that). I think Vitalik Buterin has been working on the concept since November or so of last year, but Dogecoin was out and live in December. Ethereum only had a proof of concept in the early part of this year and won't have a final release until next year.

If Ethereum can release and be everything they say it is, there's plenty of time for a community to build up around it. It is difficult for a community to coalesce around something which isn't running.

I do recognize the technicalities of Ethereum vs. Dogecoin trajectories. It just seems that like Dogecoin, most succesful things get into the wild fast and there is an MVP for people to interact with. The two year wait for Ethereum isn't ideal and with the sure rise of Sidechains (because powerful people are behind it), the deck is increasingly stacking against them.

It just seems like were talking Opera vs. Chrome, which if you remember Opera gave up and implemented webkit.

Ethereum is completely separate from the Bitcoin blockchain/network, it's a new cryptocurrency system with a much more expansive scripting system than what Bitcoin has at the moment.

Ethereum could, with relative ease, be created as a Bitcoin sidechain instead of being totally independent from Bitcoin. However, as far as I'm aware - the Ethereum "coins" called ethers couldn't be transferred, which would suck for people who bought ethers in the ether sale.

Etherum will likely continue being its own thing, but someone may also very likely fork it to be a sidechain.

I'm wondering if it's possible to use a sidechain to effectively bind two dissimilar chains together. If that's possible you could use bitcoins to run ethereum contracts and use ether to send money to a bitcoin wallet. Both systems would do well; Bitcoin for its brand recognition for digital finance, Ethereum for its generalized scripting capability.

edit- looks like I found my answer: http://bitcoinmagazine.com/12349/side-chains-challenges-pote...

I think the future will see all of these systems interoperating and we'll no longer be debating popularity.