Last week, Mashery's first "Pro Service" rate limiting client, compete.com, went live with Mashery's package of developer key management, access control and rate limiting. Compete's first outside API user is domaintools.com, which offers a nice snapshot of information on an active domain. If the domain you request is in the top million domains, this information includes a ranking pulled from compete's database.
Mashery ensures that only authorized developers have access to Compete's API. Compete is currently running a "closed" developer network, meaning that only developers preapproved by Compete are eligible for keys. I expect that they will move to an "open" network soon.
But even closed networks need control. Domaintools is subject to a Mashery-managed calls-per-second limit, so that excessive traffic to domaintools will not overload Compete's API. We also limit overall number of calls per month per Compete's specification. Mashery allows Compete to set a different calls-per-second and calls-per-month (or per day or per week - whatever time period they want) for each developer key that is issued.
One interesting outcome of this launch is that Compete has demonstrated how to extract value from an API without necessarily directly charging for access to that API.
A domaintools.com report on "programmableweb.com" generates the page below. Note the contribution from compete.com...the link enclosed links back to the actual compete.com site, which provides more information. We're told that this has turned into a nice source of traffic to compete.com.