=== please explain what is your point? === Quoth the article: "In fact, since most images and sounds on Web pages are compressed already, the modem's attempts

=== please explain what is your point? === Quoth the article: "In fact, since most images and sounds on Web pages are compressed already, the modem's attempts to compress the data a second time is futile, and just adds more latency without giving any benefit." The point is that the article itself addresses this point. === Don't we agree that compression requires processing input data stream in a window, which introduces extra latency? === No, we don't agree. Your point is correct for a specific use case of compression. However, the article describes using compression such as JPEG for images and MPEG for videos. Typically, images are not stored in raw form and compressed to JPEG only when requested (which would introduce latency, as you suggest). Rather, images are compressed in advanced and stored in their compressed form. This use case of compression does not introduce extra latency.