For journal articles, books, conference proceedings and other "things I should be citing when writing formally," I use Zotero. I won't say too much about Zotero since there is so much out there already on using it, and I figure most librarians are at least familiar with it. There's even at least one book targeted in part towards librarians on it. What I can say is I had been bopping back and forth between Zotero and Mendeley, and there were really three things that finally convinced me to stick with Zotero. First, I discovered how to annotate a PDF in Adobe, which took away one of Mendeley's major attractions for me. Second, Mendeley was bought by Elsevier, and Elsevier is gross (that's a professional judgement right there), while Zotero is open source and cool. Third, and most importantly, was Zotero Standalone and the Chrome and Firefox plug-ins that go with it. I use Chrome a lot more than I do Firefox now, so the ability to actually use Zotero in it really made me happy. But, even in Firefox I love Standalone and the new plug-in more than what came before, since I can download the citation and often the PDF full text with one quick click up by the URL. It makes me happy.
So, what about the rest? There is a whole lot more out there about librarianship than books and articles, large amounts of it either web-native or readily available on the web. For that, I use Diigo to keep track of it. Diigo is a social bookmarking tool, and while social bookmarking doesn't have the sexy sheen it did a few years ago, I love Diigo. Again, I use Chrome and Firefox primarily, and Diigo has an extension and toolbar, respectively, for those two browsers that let me automatically add and tag bookmarks really easily. There is also a toolbar for IE, and some possibly third-party add-on for Safari, in addition to a bookmarklet that can be added to any browser. They also have Android and iOS apps. Okay, I can't say I use the iPad app much other than pulling up recipes I've saved (I use Diigo for a lot more than library stuff), I never use the Android app on my phone, and I dislike that I cannot add a highlighter to mobile Chrome in iPad (you can for Safari). Still, I'm mostly in apps on my iPad and Galaxy anyway, and I've got a solution there. I get almost all of my library information from Feedly and Twitter, whether in the web versions or in apps, and I use IFTTT to automatically send things from those tools to Diigo. I have recipes to automatically add private bookmarks, which I go back to tag and make public later, whenever I save something in Feedly, favorite something on Twitter, or tweet out a link.1
Now, of course, gathering a whole bunch of stuff is one thing. Getting back to it is another. Thankfully, Diigo does not require you to go to diigo.com to get at your library. The Chrome add-on automatically includes a box with Diigo results every time you search Google, and the Firefox toolbar has a search bar that also searches Google and Diigo simultaneously. You never need a separate search, which is great because I'd never remember to do so.
But wait, there's more! The Chrome add-on and Firefox toolbar also let you annotate webpages. You can both highlight text and add comments. There is also a setting to allow you to see other Diigo users' annotations, but I can't say having that on has been really beneficial for me, so I keep it off so I'm not distracted. You only get 1000 highlights a year with the free version, but I haven't even come close to that. If you do go a little crazy with the highlighting, or want to cache a lot of pages (which I never do even though I get 30 free), you might look into one of the paid versions. I'm sticking with free for now, though if the full-text search that comes with the Basic plan is really great I might try that out, but I'm not testing it myself (or at least not until I'm off a grad student's income). I also do not take advantage of the social options in Diigo, since I don't know anyone else who uses it, though you could totally change that by signing up and following me. Which would give me even more information to read and then manage, and that would make me oh so happy.
1) If I follow you on Twitter, and it seems like I'm always favoriting things, it's because I'm saving it to Diigo.
1) If I follow you on Twitter, and it seems like I'm always favoriting things, it's because I'm saving it to Diigo.