I’ve seen him posted here multiple times...who is that?
Giorgio Tsoukalos, the “Ancient Aliens” guy. With the hair.
http://knowyourmeme.com/memes/ancient-aliens
About
Ancient Aliens is a series of image macros based on History Channels TV series with the same name starring alien expert Giorgio A. Tsoukalos, who often tends to explain inexplicable phenomena as the direct result of aliens or extraterrestrials being on Earth. In a somewhat similar fashion to Bill OReillys You Cant Explain That series, the Ancient Aliens macros exaggerate Tsoukalos beliefs to such an extent that they become humourous.
Origin
The still shot of Giorgio A. Tsoukalos originated from the History Channel series Ancient Aliens[1], a documentary series that explores the possibility that aliens may have visited in the past. The program is directed and produced by Giorgio A. Tsoukalos and first aired on April 20th, 2010.
Spread
Giorgio A. Tsoukaloss unworldly appearance and predictable resort to aliens in explaining various mysteries of human civilization caught many peoples attention in the audience. As early as in November 2010, his alien repertoire became a popular subject of lulzy mockeries when it reached 4chans /b/ (random) board[3], spawning a steady stream of images centered around an exploitable screenshot of Giorgio A. Tsoukalos from the TV series.