8. A system comprising: a server having a processor and a computer-readable storage media; a transforming module executed by the processor to receive first content requested by a browser and to identify certain types of markup tags and scripts in the first content as not meeting a predetermined safety criteria threshold, the transforming module correcting the first content by removing from the first content the certain types of markup tags and scripts that do not meet the predetermined safety criteria threshold prior to transcoding; a transcoding module maintained on the computer-readable storage media and executed on the processor to transcode the first content requested by the browser from a first-markup language that is not supported by the browser into a second-markup language that is supported by the browser; and a link rewriting module maintained on the computer-readable storage media and executed on the processor to: identify, in the first content, an original uniform resource locator (URL) reference to second content stored at an external content source, the external content source being an external content provider in communication with the server via a network; rewrite the original URL reference in the first content to be directed to a proxy URL of the server to enable the server to act as a proxy to the second content at the external content source; replace the original URL reference with a proxy URL reference to the proxy URL in the first content transcoded into the second-markup language; and provide the first content transcoded into the second markup language having the proxy URL to the browser.
8. A system comprising: a server having a processor and a computer-readable storage media; a transforming module executed by the processor to receive first content requested by a browser and to identify certain types of markup tags and scripts in the first content as not meeting a predetermined safety criteria threshold, the transforming module correcting the first content by removing from the first content the certain types of markup tags and scripts that do not meet the predetermined safety criteria threshold prior to transcoding; a transcoding module maintained on the computer-readable storage media and executed on the processor to transcode the first content requested by the browser from a first-markup language that is not supported by the browser into a second-markup language that is supported by the browser; and a link rewriting module maintained on the computer-readable storage media and executed on the processor to: identify, in the first content, an original uniform resource locator (URL) reference to second content stored at an external content source, the external content source being an external content provider in communication with the server via a network; rewrite the original URL reference in the first content to be directed to a proxy URL of the server to enable the server to act as a proxy to the second content at the external content source; replace the original URL reference with a proxy URL reference to the proxy URL in the first content transcoded into the second-markup language; and provide the first content transcoded into the second markup language having the proxy URL to the browser. 9. The system as described in claim 8 , the server being further configured to subsequently receive a request from the browser for access to the proxy URL by selection of the proxy URL in the first content by the browser, access the external content source based on the original URL reference to download the second content from the external content source, and transcode the second content to the second-markup language for providing transcoded second content to the browser.