No subject

I don't know about studies, but the way I do it is if I'm marking a deep 
page, I usually put it in a To Read folder.  Then if I ever get around to 
reading the page, I'll either delete the bookmark or add the site to an 
appropriate folder.

Citations:
"Keeping found things found on the web"
Jones, Bruce, Dumais,  CIKM '01, Atlanta, GA, 2001, 119-126
available at:
http://research.microsoft.com/~sdumais/CIKM%20paper%20camera-ready.pdf

Information archiving with bookmarks: personal Web space construction and
organization
Abrams, Baecker, Chignell, Conference proceedings on Human factors in
computing systems,1998, 41 - 48.
Available at: http://www.dgp.toronto.edu/people/RMB/papers/p6.pdf

"Fast web by using updated content extraction and a bookmark facility"
Ebina, Igi, Miyake, ACM SIGCAPH Conference on Assistive Technologies 2000,
64-71