I don't know if anyone else is like me when they're doing research. I get side-tracked when I'm browsing through census records, old newspapers, reference books, the web, etc. All sorts of things catch my eye like interesting names, names that seem familiar, the ads and articles in newspapers, or other people's genealogy write-ups on people I'm not related to (although, I like to see how they did their research, what records they used, etc.)---you name it---and the next thing I know, an hour or two has gone by. I've had to tell myself twice today while browsing a census record, "Focus, Catherine, focus!"
In order to stay focused, I'm learning that if anything looks like it might be something I want to look at more closely later (or for any research, for that matter), I save it to my hard drive or to my ancestry.com shoebox, or I cut and paste it into a Word document and include the link or make a note of it and the reference. I should probably use Evernote for this (I use it for other things, so why not genealogy!) or upload these files to Dropbox (although my Dropbox is usually used for work files and it's about 37% full) so they'll be available to me anywhere that has internet access as suggested on several genealogy blogs. I like things that are searchable. I think I need to improve my research system.