Some good folks at the University of Hamburg published an update to some long standing historical numbers in web usage research that reveal the way users are browsing the web has changed dramatically over the last few years. Here's the punchline:

Table 1: Comparison chart of three long-term studies

Catledge & Pitkow3

Tauscher & Greenberg3

This Study

Time of study

1994

1995-1996

2004-2005

No. of users

107

23

25

Length (days)

21

35-42

52-195, ΓΈ=105

No. of visits

31,134

84,841

137,272

Recurrence rate

61%

58%

45.6%

Link

45.7%

43.4%

43.5%

Back

35.7%

31.7%

14.3%

Submit

-

4.4%

15.3%

New window

0.2%

0.8%

10.5%

Direct access

12.6%

13.2%

9.4%

Reload

4.3%

3.3%

1.7%

Forward

1.5%

0.8%

0.6%

Other

-

2.3%

4.8%

In particular, note the dramatic increase in new window usage (including tabs). Usage of the back button is decreased, probably directly related to new window/tabs as an alternate page view management strategy. This work also produced the sexiest image of the conference, a positional click map aggregated across all the users studied and all the pages they viewed.
Map with link activity areas of Web users.

The dense region at the lower right is the search engine next button.  WWW has a long tradition of publishing the proceedings online.  This year the papers are available in XHTML, here's the link for this work.