Table 1 lists the most frequently observed ``UserAgent'' HTTP headers observed within the Home IP traces. From this table, it is easy to make a common misconclusion about web clients, namely that the set of web clients in use is extremely homogeneous, as nearly all browsers observed in our traces are either the Netscape Navigator [28] or Microsoft Internet Explorer (MSIE) [26] browsers running on the Windows or Macintosh operating systems. However, there is significant heterogeneity arising from the many versions of these browsers and their widely varying feature sets. Furthermore, we observed a total 166 different UserAgent values within the traces, representing a wide range of desktop systems (MacOS, Win16, NetBSD, Linux, etc.) More significantly, however, we saw requests from a number of exotic clients such as Newton PDAs running the NetHopper [1] browser.
Table 1: UserAgent HTTP headers:
this table lists the 10 most
frequent UserAgent headers observed in the
traces. ``Other'' browsers observed include PointCast,
Cyberdog, Mosaic, Opera, Lynx, JDK, and NetHopper.
Internet services that do not want to limit the effective audience of their content must therefore be able to deliver content that suits the needs of all of these diverse clients. Either the services themselves must adapt their content, or they must rely on the emergence of middleware services (such as in [13], [14], and [7]) to adapt content on the fly to better suit the clients' particular needs.