If you are in the NIH ratrace, then following NIH Funding [@NIHFunding] can be helpful. Yes 95% of what is tweeted is irrelevant. But its still better than the days when it came to the library, in hard copy, and you had to go somewhere else to read it.
NIH Guide for Grants & Contacts: funding opportunities & more. (Official NIH Office of Extramural Research account.) Privacy: http://1.usa.gov/GY3GNm