A gap filler often placed at the end of a sentence or in order to complete a thought; carries no significance.
The origins of "but yeah, duded" are not completely known. It is believed to have started in small circles and gained notoriety through the internet.
Derived from "so yes" and "dude". "So yes" is simply used when people have nothing to say; "duded" is the misspelling of "dude", a reference to the person you are talking to. People who often say "but yeah" avidly misspell words.
Kevin was invited to Emily's house in order to watch old Law & Order episodes. However in the middle of the episode Kevin became too enthralled and knocked over Emily's prized trophy. Emily became so mad that she bit Kevin, which caused Kevin to proclaim "you bitter (sic)." Upset by what had just unfolded, Kevin decided to leave and go home. He was upset at society's injustices and decided to let it have its own way. At home, he invited Sharyn over, but she could only come next month because there must be a month's notice before anyone can come. But yeah, duded.