"However marked the World Wide Web may be by dates and updates, by versioning and revision, however pocked it may be by expired links, and however haunted by the promise of "soon, not yet," posting something on the web today means publishing into a continual, continuous present that relies more on dates of access and experiences of 'WELCOME' than on any date of publication" (Gitelman, 145).
I feel that this continuous present World Wide Web is derived from its function as a space. A space's history has a difficult time representing itself, and is prone to errors in the same way the Internet is. Expired links, moved pages, outdated protocols, etc all have analogous translations in real space.
Think of a diner. Diners tend to serve the same food and provide the same service throughout the scope of their existence. The aesthetics may change, the building may change, the management may change, but its existence as a diner is determined by its content, which is food. This space is one defined by what it provides. A web page, throughout the scope of its existence, may go through various changes - formatting, URL, coding overhaul - but its existence is ultimately determined by what it provides, not what it looks like and "where" it is as it provides.
The Web, however esoteric it may be, is still governed by the rules of space. Gitelman goes on to say "But the present tense of the World Wide Web follows an ancient rhetorical tradition at the same time that it does the febrile logic of "late" capitalism and global finance. This is the present tense of hermeneutics, writing about writing, and interpretive processes more broadly." This present tense is what so closely links the Web to physical space.
The Wayback Machine serves the same purpose as old pictures of the diner hanging above a booth. You can peer into what the Internet, this ever changing space, looked like in its early years, before renovations, staff changes, interior decoration, design changes, recoding, protocol alterations, etc.