Chrome: If you're researching a project online, or you tend to end up with hundreds of tabs open, it's hard to keep track of everything. Contextinator is a Chrome app that helps manage those sessions by dividing them up into various projects.
When you create a new project in Contextinator, you're taken to a screen where you can add bookmarks, tasks, people and emails. As you add more things to your project, they all exist in a single window, and all of yours open tabs are saved. When you load up the project again, all your tabs are restored, and you're taken to the project homepage with your tasks, bookmarks and everything else.
Essentially, it makes it so you can save all your research — whether it's for a PhD or a trip to Rome — in one place and then open it all instantly. If you're researching two things at once, you can save each of those browser states all in one project so you don't get confused.
Contextinator also integrates with services like Gmail, Evernote, Dropbox, Google Drive and Trello so that when you visit one of those sites you can quickly add more info to your project. It's not the most elegant app, but it's robust and useful for big projects. Check out the developer's website for a few videos of Contextinator in action.