This is the best way to keep track of new journal articles, grant announcements, and any other news that you are interested. Basically, it is a blog/RSS feed reader. What's great about RSS (really simple syndication) is that most sites have RSS feeds (including this science hacks blog). After you subscribe to a feed, newly posted articles from you favorite sites will pop up instantly in google reader. For me it keeps me up to date on the 100s of things that are coming out every day. It's a stress free way of staying plugged in to what's going on in science or any other area that you are interested in.
1. You see articles as soon as their published
2. Synced on all devices and is accessible offline
3. Share articles with friends via email, facebook, twitter, etc...
Science use case:
When I was searching for jobs this service was a life saver. It alerted me when ever new jobs were advertised in Science, Nature, and Cell. I used this in combination with evernote to keep track of all my postings. Lately I've been using it to keep track of new journal articles. You can create an RSS feed for anything that pubmed can search for by performing your search, pulling down the "send to" menu bar, and selecting "send to rss". If you click on the newly created link it will dump you into google reader and you are good to go. The feeds that I have set up are for my favorite journals, authors, and keywords.