The third video

You have to find a similarity with these videos
Think time stamp
the answer is http://www.thisisnottom.com/340/(highlight to expose)

there is a sign, just google it, it's the most obvious thing
the letters at the bottom are clues, comment if you want explanation

the answer is alaska (highlight to expose)

now you get a picture with a porcupine
the answer is listentoit (higlight to expose)

you've reached 1.4.1

P.S. As you may already know, ThisIsNotTom was created by John Green back in 2009. He's now a best selling author. The movie The Fault In Our Stars was based on a book by him. If you liked TINT and also The Fault in Our Stars, you should check out the book that made me cry when I was supposed to be a super macho teenage boy, Looking for Alaska. You can get it here.