1. At least one machine-readable memory comprising machine-readable instructions that, when executed by at least one processor, cause the at least one processor to perform acts comprising: receiving, at a current time, at least one request for at least one object, wherein the object comprises at least one of a file stored on a server or a webpage hosted on a website; determining whether a reputation score for the at least one object exists, and if so, determining whether the reputation score is valid based at least in part on a difference between the current time and a previous time when the reputation score was known to be valid; and in response to determining that the reputation score does not exist or is not valid, computing the reputation score for the at least one object by: instantiating a protected virtual environment in which to execute the object, executing the object within the protected virtual environment, suspending execution of the object within the protected virtual environment, and analyzing at least one aspect of the protected virtual environment to determine the reputation score while the execution of the object is suspended, the reputation score is computed substantially in real time with the at least one request for the file stored on the server or the webpage hosted on the website, the reputation score indicating whether the file stored on the server or the webpage hosted on the website, when loaded into and executed within the protected virtual environment, is associated with an acceptable level of risk.