Threaded page loading. Mosaic needed to download all text and graphics before displaying any part of a web page. This was painfully slow over modems. Netscap

Threaded page loading. Mosaic needed to download all text and graphics before displaying any part of a web page. This was painfully slow over modems. Netscape's huge innovation was to partially render pages while resources (mainly images) were downloading, giving the appearance of a faster web.