citeulike can easily be downloaded locally: simple clean, easy, doi matching, shared groups, LikeUCite can download all PDFs as well making a local library that I sometimes move into Paper (OSX) locally for archiving. I use Bibtex export for preparing papers. I also add a tag for a particular manuscript we are writing and then easily download the set. Collaborating with (willing) co-authors also makes it possible for multiple users (in a group) to add papers. - Jason Stajich from twhirl

If I haven't invested yet in Connotea, can I import old Endnote libraries into CiteULike? - Heather

I started my library with connotea but I think I would use citeulike now just for the pdf uploading tool.. I use this scientific-social-boorkmarking tool because they understand the DOI or the pubmed-id's. However, once a month, I transfer all my bookmarks from connotea to http://del.icio.us because, at the end, its 'network" option is the best tool for knownledge discovery : http://del.icio.us/network... - Pierre Lindenbaum

Duncan also takes indecent liberties with the Bioperl paper to describe buggotea: http://www.nodalpoint.org/2006... - Jason Stajich

"Liking" this to remind me to try CiteULike. - Bill Hooker

Google Trends shows that CiteULike is more popular. Both could have better group features. - Martin Fenner

Pierre - Just today I was thinking again how Nature could try to combine Nature Network with Connotea to provide a page in NN for paper recommendations (based on the contacts libraries in Connotea). Also maybe analyze the papers published by the user to give recommendations based on a search for related papers (automated query to pubmeds related papers ?). To be a bit fancy they could give some options to filter them. Hide some of the users contacts or pick a selected group of journals to filter etc. - Pedro Beltrao

You may want to try http://2collab.com/ too - Rafael Sidi

I'm going to try CiteULike soon. I tried it soon after launch and didn't have a good experience, but I understand it's come a long way. The only thing keeping me with Connotea is inertia, and the fact that I think citeulike is the dumbest name ever. Sorry, Mr. Cameron. I tried 2collab http://synthesis.williamgunn.org/2008... but there are all kinds of weird design decisions that just don't make any sense to me and the import and export still need work. - Mr. Gunn

I use Connotea, but the problem with online ref. managers is when you try to access articles from journals that require subscription. Which has me going all the way around to login through the university library's proxy and then retrieve the article. The middle way I've found is by saving the pdf's locally through Zotero, and then uploading the references to Connotea via .ris or .bib file export from Zotero... So I get pdfs right there in my hands to read right away, and saving the refs online for Web 2.0 - Ntino

Thanks, all. Giving citeulike a shot. - Chris Miller

Why not combine Connotea and Nature Network? I see a lot of synergy. - Martin Fenner

In related news, the long (January) overdue update to make Endnote work with Word 2008 for Macintosh was just announced. - Martin Fenner

We're aiming to set up an infrastructure that'll allow all our apps (and potentially external ones too) to share data with each other. NN-Connotea should be one of the first things to come out of that. Don't know about the timeframe though. - Euan

I'm at a network conference this week looking for techniques to help integrate into connotea for searching through the graph of information there to help with content discovery, lot's of good ideas here, and, oh, yes we are looking at nn-connotea integration, but that should not be too much of a shock. - Ian Mulvany

By the way, the Connotea RSS feeds are still taking an age to come through. I just got some in Google Reader from 9 days ago! How can this be speeded up? - Sally Church

Was using both sporadically. only CiteULike mported all my local references (1895). Have a huge tag-cloud there now. As long as there is no full integration with my wordprocessor, online references are pretty useless to me. - Björn Brembs

That last bit is critical. Works for me since not writing papers anymore. - Deepak Singh

trying citeulike now, connotea feeds disappearing and bibtex export does not seem to work correctly - Frank

The Connotea delay is (I think) because they introduced a new server to handle some types of traffic. Teething problems with that, maybe... - Euan

CiteULike, since it provides RSS feeds on several levels, e.g. most popular - joergkurtwegner

Well whatever it was, the latest connotea bookmark went through in 8 mins, w00t! - Sally Church

what about connotea vs 2collab? if you skip CiteUlike, my experience is connotea is better - Alexey