These days I'd avoid bookmarking in general, unless from the major sites. The smaller bookmarking ,directory sites aren't worth the trouble they will bring in the long run.
Which bookmarking sites you are talking about??? As far as I know many well known high PR bookmarking sites is working properly. Not sure about directory sites..
In my concern only submitting website High Page Rank is not effective, you have to also check the site Domain Authority, Indexing, Caching etc. Because these are also a important factor when you doing off page submission work.
I think high pr social bookmarking and Directory submission sites are still important for keyword ranking and instant traffic on your sites to get benefits.