What is So Jesus?
A little-known person/object/trend you've discovered before it's caught on, but that you know will become popular and mainstream way after the fact.
(i.e. How Jesus only had a following of a few people, and then modern Christianity became trendy and caught on way later.)
"Did you see Seth Rogen on Freaks & Geeks?"
"He's so Jesus, his fame will explode in a few years."