I would like to be up to date with published articles on my research topic. I saw that pubmed allow to subscribe to a research (there is an RSS link just below the research box), so I added the RSS to my Outlook account. The problem is the new feeds seem not very frequent, and the articles are not even recent! (I added the RSS feed in November, today I got an update with a paper published in September 2012, which by the way I had already read). Do you subscribe to this kind of RSS? Is it a problem of Pubmed, or maybe of Outlook?
In this case, it's a PubMed issue, but it's actually an issue that most of the online aggregators and literature databases share: for some reason, which I have never managed to understand, databases update is slow.
If I take a given journal indexed in PubMed, Phys. Rev. Lett., let's see what are the most recently added articles:
You see that they are two months old (dating November 21, while I write this answer on January 25). Both the web search front-end and the RSS use the same database, which is not fast to pick up papers from some journals. Your mileage may vary, however: the most recently added PLOS One articles are dated January 16, a mere 10-days old:
I say that most databases I know have the same issue. From experience, Web of Science has the slowest update, while both PubMed and Google Scholar are better. For my field (chemistry), SciFinder has the fastest update speed.