Actually, we primarily look at just the clickthrough rate on the links to determine someone's influence. Influence is highly categorical.

For example, if I tweet about tech things, I'll get many clicks since most of my followers are techies. If I tweet about horses, ... not so many clicks and therefore I have a poorer influence for "horses".

Klout and # of followers abstract away these fine-grained details that, IMO, are critically important in determining social influence.

Klout scores really show more of a relational-sort of data. I actually don't place much faith in the quality of their "ranking" system, IMO.

Thanks! We're using it on our site now to see who is tweeting about the launch! Real-time results ftw!

You might be able to do it with HubSpot or PostRank, but we couldn't find anything simple. SO we built it!

ViralHeat and SocMetrics both provide similar features, but they cost money and are more complicated.

We wanted to keep things ultra simple. Oh, and FREE!

It depends on how you want to charge for your web app. Check out Willet (http://www.getwillet.com).

[Full disclosure: I'm a Willet co-founder.]

- Web page says "US and Canada" only.

- The FAQ says that "Willet is a super fast and simple way to buy digital goods and services". Surely you are targeting developers, ie. the seller, so you should tell us that Willet is a super blah blah way to sell digital goods and services?

- Willet seems designed for very small transactions and has no support for subscriptions.

- Your site does not tell me how I, as a seller, gets the money. Surely that's at least half of the point of services such as Braintree -- ie., the merchant account.

Yeah, most people don't see 'spare change' as 'real money', funnily enough.

We're considering allowing users to have a Willet account (ie. new user name and pw). Aren't people sick of having so many logins these days? That was part of the incentive to use FB - keep things simple!

I personally don't mind creating an account for a service I find valuable. Especially if it's going to be dealing with money. In that case, I would rather create a dedicated account than rely on some external party.

I think when you're talking about a payment integration system, having to create an account is not what will stop "sellers", as you call them, from signing up. It's probably different for end users though.

Fair enough. I'll bump this to the front of the feature queue!

I think it goes both ways. I personally prefer not having to create an account, but others are concerned about privacy, don't want their accounts linked (like in BSG), or don't have accounts.

Willet works the same way. Spend away until you reach $3 of purchases, then you enter a credit card at this point. We securely store your credit card info in our digital vault. When you reach your limit again, we'll run your credit card and email you a receipt!

That's what we're aiming to do!

Exactly! Furthermore, you can charge small amounts. Look at all of the success of the mobile app stores and in-app payments. YOU CAN DO THIS ONLINE NOW!