Captcha-free throttling

A throttle server for throttling access to a web resource, comprising:

• a receiving mechanism configured to receive a request to access the web resource, wherein the request is associated with a computing device used by a user and is redirected from a server providing the web resource;
• a throttling mechanism configured to determine a restricted resource, if any, the computing device has previously accessed based on the presence or absence of a unique mark associated with the computing device, wherein the restricted resource is different from the web resource corresponding to the request;
• a response-generating mechanism configured to generate, based on the determination, a response indicating whether the computing device meets a predetermined requirement for accessing the resource;
• and
• a sending mechanism configured to send the response to the server providing the web resource, thereby facilitating access throttling to the web resource.

A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for throttling access to a web resource, the method comprising:

• at a throttle server, receiving a request to access the web resource, wherein the request is associated with a computing device used by a user and is redirected from a server providing the web resource;
• determining a restricted resource, if any, the computing device has previously accessed based on the presence or absence of a unique mark associated with the computing device, wherein the restricted resource is different from the web resource corresponding to the request;
• based on the determination, generating a response indicating whether the computing device meets a predetermined requirement for accessing the web resource;
• and
• sending the response to the server providing the web resource, thereby facilitating access throttling to the web resource.