The Baader-Meinhof Phenomenon
Baader-Meinhof is the phenomenon where one happens upon some obscure piece of information – often an unfamiliar word or name– and soon afterwards encounters the same subject again, often repeatedly. 


Anytime the phrase “That’s so weird, I just heard about that the other day” would be appropriate, the utterer is hip-deep in Baader-Meinhof.


http://www.damninteresting.com/the-baader-meinhof-phenomenon

Wikipedia definition:
A common name for a form of synchronicity where one happens upon an obscure piece of information, and soon afterwards encounters the same subject again.