Web sites are, in my view, a necessity, but they are not a part of any but an electronic press kit.
However (and this is part of what I think the web is for), it is quite common for performance poets and agented authors and authors on huge presses to have press kits -- either print-out-able as a press kit (all the info in a clean and simple format or in an attached .pdf) or an "online press kit" as part of their sites.
Susan Wheeler, Thalia Field, Shelley Jackson, Jeanne Beaumont's presence at WW Norton, and the Janet Holmes / Rachel Loden / Stephanie Strickland site at pomegranate were author websites I looked at particularly carefully as far as the run of what most authors have made or make vs. what they are generally provided. This is quite different from the better "academic / author" website like Juliana Spahr's, IMO.
The press kit for the performance poets generally includes sound files, links to poems, links to reviews, self-published or self-reprinted (electronically) poems, links to the blog, poetics statements, a schedule / calendar of dates, etc.
Among my models for the press kit were those on Iris Berry's, Exene Cervenka's, Daphne Gottlieb's, and some other websites, although mine is not that glossy right now.
A pet peeve of mine is noncommercial authors with a ".com" rather than another (noncommercial) extension.
***Link to first online review: http://www.sidereality.com/volume2issue4/reviewsv2n4/reviewofdadada.htm