Topic: [ON HOLD - 300 BTC] Make a bitcointalk forum plugin to allow tipping via BTC - page 3. (Read 8406 times)

After actually bothering to read the details of Mike's proposal, the forum knows the private keys it's sending, and can withhold and spend enough of them to itself in order to satisfy their fee.  It could send the private key of the change address of this fee transaction to itself to the person being tipped.

Edit: Agh in too much of a hurry...  The tipper then wouldn't be able to double spend the fee change as desired, so the onus would have to be on him to include a private key with exactly the right amount.

If someone sends 1 satoshi and the tipping service charges a fee, the recipient will get less than 1 satoshi. Then they might send that amount on to someone else. That's one possibility. I don't know how common that'd be.

I guess I'm not sure what the goal is. Reddit's bitcointip posts whenever someone gets a tip, which advertises the tipping system and gets people excited about Bitcoin. I was thinking that having a public tally of tips would get people interested in a similar way.

Regarding the last point, the forum could require payment URIs send it a fee in order to publish it, couldn't it?  That would solve the tip inflation problem, and provide a source of revenue for the forum.

IMO the decentralized/universal nature of Mike's solution is too beneficial to overlook.

Edit: I didn't think about carefully about how people could cheat that...

Agreed about requirements, but why would you ever want to tip somebody less than 1 satoshi? That level of value is in the extreme-micropayment range, if I got a 1 satoshi tip I'd take it as an insult!

Do tips really need to double as a reputation system? The goal is to encourage posters to post more, right, not act as a publicly visible measure of reliability. If you just don't display the total amount of tips gathered by a user, or just show a list of usernames that pressed the tip button on a post, then the issue of tipping yourself goes away.

IMO an E-Wallet is desirable for this because:
- People can instantly make very small tips without having to pay a large fee (relative to the tip amount). They could even send amounts smaller than 1 satoshi.
- People are more likely to keep any tips they receive in the system if withdrawing their BTC requires a higher fee and more time than sending tips does.
- I think that the best way to prevent people from infinitely inflating their "tips received" count is to charge a percentage fee based on the BTC amount sent. You could do this with Bitcoin transaction fees, but it's more complicated for the sender.

The exact requirements clearly need to be figured out before someone starts working on this.

This is where that mythical decentralized reputation/identity system would be useful.  I see that bitcoin-otc identities already (at least many of them) have bitcoin addresses associated with them so tipping based on otc usernames would be trivial.  Is there anywhere that is linking forum names and otc names together already (decentralized or not)?  Of course that still requires setting up another account to receive tips and/or holding unclaimed tips somewhere temporarily for users without an account.

From what i understood this relies on someone else services, and there is no easy way to skip this.
Decentralizing this external entity doesn't help on his security.

I would love the 300BTC but even given that i create this service using my infrastructure, how could you relay on me with your money? The only answer is that you couldn't.

So what happens on reddit if the user never picks up the coins?

It's better to think in terms of purely decentralized solutions rather than relying on branded third party services. Otherwise you're not really addressing theymos' concerns, just moving them around to some other party.

So I'd start by extending the payment protocol (er, once we ship v1) to be able to mark payments as donations. A donation is processed like a regular payment but the output is not marked as spent in the wallet, it's marked as donated instead. Donated payments can be deliberately double-spent after the user clicks through a confirmation screen. This means if the user doesn't pick up the tip and eventually the tipper gets bored and wants his money back, they can do that easily from within their wallet software.

The Payment message would then be extended to contain not only transactions, but also a list of private keys that can correspond to the tx outputs. The client would submit the Payment as normal to a URL on bitcointalk.org which would simply take the submitted data, and send it as an attachment in a mail to the user. Then the forum would forget all about it. Anyone with access to the file can claim the tip, but it'll end up in the users mailbox and nowhere else.

Advantages:

• If the forum gets hacked, only newly sent tips can be intercepted and stolen. It'd be easy to set up a bot which tips itself every so often to detect tips that go missing.
• The forum is not holding money for anyone, just routing some messages around, so there's no additional legal complexity.
• Tips are pure P2P, as fits Bitcoins design
• It's a system that's trivial to integrate with any forum, blog, wiki, whatever. As long as the software can accept an HTTP POST and send the attached data to the user via email, you're done.

To go a step further for users who get tipped and want to auto-accept tips in future, with a more complex plugin they can provide the forum with some addresses and the forum can automatically spend the submitted tips to the user themselves. That way they don't have to open the mail attachments.

Actually am working on something similar (in terms of escrow) for my own project - if it turns out to be useful then will be sure to let others know (not promoting any particular service at this stage though).

This looks better but still a little too much. The ideal situation would be a service where you would simply get json-rpc details to a hosted bitcoind instance where the third party ensures security for the hosting. Does that exist?

Am not sure how much I would trust any online wallet but I will say that the support from WalletBit is quite good (there you go Kris - something positive from me at last).

Are there any other services that will host a wallet in a secure and safe fashion for you?

We had this bounty on Rugatu for a while (asked 30 Sep), people are already working on it but it gathered around 6btc only.

http://www.rugatu.com/questions/3575/can-you-make-a-bitcoin-smf-mod

I wouldn't be promoting Coinapult for this - there is no user support for that service (I only got my 1 BTC back becuase Yankee was nice enough to do so).

I think an important feature of the reddit and twitter tipping bots is this: they allow you to tip people who haven't done anything special.

In other words, the recipient doesn't need to have set up a tipping account, or advertised his address anywhere. On reddit you can just send a tip to someone who has never heard of btc, and that's the beauty of it.

So, this potential forum system, probably requires this. This is also why the practice of people putting their btc address in their sig is not equivalent. I want to be able to tip someone who has never solicited it.

I agree the forum shouldn't fuss with building an ewallet to hold the funds for this. Instead, it could use an API to a secure wallet system, like Coinapult.com 

Idea:

1) I like a comment Theymos made, so I click the "Tip User" link (maybe similar to how theymos showed in his screenshot)
2) A window pops up, with a BTC address and QR code
3) Upon receipt of btc to that address, the forum emails the user (via coinapult.com api) his donated coins.
4) User claims the coins at his leisure

With this system, the user's email address is never exposed to the public. And, the user never needs to enter a BTC address into his profile. And, the forum doesn't need to host any wallets or store funds at all.

Thoughts?

Why would the forum need to host wallets?

Users could just provide the forum software with some public keys and have a consistent way to format bitcoin: URIs. I can imagine an integration with the payment protocol in future to produce signed payment requests. But the money goes directly from tipper to tipee and the forum itself never touches the money. It means to pay a tip is 2 clicks instead of 1 (click the link to open your wallet program, click approve), but once the payment protocol starts rolling out wallet software could be instructed to auto-approve small payments that are signed by the forum.

If you wanted, you could have the forum monitor the block chain and when you see an address be used, switch to the next for better privacy.

I disagree that bitcoin can't handle micropayments, by the way, for the sorts of sizes and frequencies that tippers would consider it should work fine. But in the odd case where it wouldn't, wallets could simply delay the payment until another larger transaction was made and tack it onto that one.

That said, I agree with Theymos on people using it - it's probably better to wait and see if the redditbot has longevity. If it does, analyzing what made it successful where other attempts failed would be useful, then we know exactly what to recreate. For instance, is it convenience? Immediacy? The ability to show off your charity by requiring tip commands to be public?

As you can see, I stuck it under my avatar as personal text, so sig & avatar hiding doesn't work. Even though it's longer than the table column, double clicking it selects the obscured part.

These sound pretty solid.

On the other hand, anyone who wants to be tipped in BTC can put an address in their sigline. Why is there a need for more software?

Vaguely related, how's the new forum software coming along?

I'm interested to see what I can do. I am confident I could build a tipping backend system, https://tippingService.com, as mentioned by Theymos with a tipping API. I'm just not sure I want the responsibility of handling wallets that might end up with a lot of coins that are not mine.

I will see if others are interested in building this as well cause I'm not going to 'risk' working on this and see somebody else snatch up the bounty before I complete the work  

The only time the wallet would have to be hot would be for a withdrawal and that could be done every hour only on the backend so it isn't that hot. If you set up a minium amount for withdrawal or move the fee to the withdrawal that would make so people keep there coins in the site longer as well. You could also set a maximum so people can't use it as an e-wallet, but I understand it would just be one more stressful things for you to handle.