I'm doing a (tangentially related) twist on this sort of thing, so I'll ask you the questions that haunted me for months until I could answer them about my own project:
Who's going to use this?
I mean, what's the intersection of people that are computer-articulate enough to know what to ask for ("convert this file for me"), but don't know how to do it, and/or are willing to spend the extra minute or two to post and manage the "favor"? Especially when "know how to do it" means "google for the free web app that does it"?
And who is going to spend their time doing these favors, with no reward except some ethereal concept of "points" that can only be redeemed for doing the things I can already easily do myself (see above)? Realize that you're competing for attention from facebook/twitter/HN. And MTurk, which actually pays.
At this point, nothing. If/when that proves to be a problem (probably sooner rather than later if the idea/site proves popular), then my initial plan is to verify emails, require unique emails on registration (obviously), and keep email addresses of deleted accounts on file for a short amount of time.
That would keep someone from deleting an account and immediately recreating it with the same email, so the person would instead have to use a different valid address per account, which probably is more trouble than it's worth to just participate in the site (at least doing that would be kind of fun).
Any thoughts on that? Your idea of mobile number verification is also an option, although it's a little too extreme for me to try unless things get bad.
Like the other comments noted, you won't go far with email verification alone (they might even use a completely unrelated email address). You can probably use a combination of email address similarity and ip address uniqueness but I think mobile verification would be much more reliable(and thanks to cheap sms via twilio, won't break your bank)
I think a bunch of services have caught on the + and . tricks in gmail. I'm not sure but it seems like my attempts have been blocked. Can anyone confirm?
I thought about doing that before posting but decided that the HN-type crowd would probably plow through them in a couple minutes so it would largely a waste of time (since posting an actual solve-able request takes at least a minute or two each).
If you developed this you could no doubt seed it quickly with some scripts or something. I don't think this would be wasted time, I checked it out... if there was something to solve I may have, but there wasn't and it's unlikely I will ever return to your site.
Even if the HN-type crowd plows through it, you might find they come back again because they got some reputation and actually got involved.
It would be a shame to see you do all the hard work on getting this thing built but it not to be a success for not doing the easy bit like seeding some data.
I've heard of this place that's been around for decades where you can log in, ask questions and quickly get answers for free in real time from knowledgeable people. I believe it's called IRC.
Mechanical Turk is a marketplace; are you planning to provide the opportunity for people to purchase points in the future? Sounds more like Experts-Exchange meets StackExchange.
Interesting idea, that hadn't occurred to me. That is one of the reasons I've chosen to leave closed favors viewable on the site, though - so people can browse through them and learn from them if they'd like.
Who's going to use this?
I mean, what's the intersection of people that are computer-articulate enough to know what to ask for ("convert this file for me"), but don't know how to do it, and/or are willing to spend the extra minute or two to post and manage the "favor"? Especially when "know how to do it" means "google for the free web app that does it"?
And who is going to spend their time doing these favors, with no reward except some ethereal concept of "points" that can only be redeemed for doing the things I can already easily do myself (see above)? Realize that you're competing for attention from facebook/twitter/HN. And MTurk, which actually pays.