Does Descriptions Boost Views?

Does applying loads of text in the description box plays a part in searches?
Or is it just tags that does this?

Use your main-keyword as the first word in your description and add some more primary keywords after.. Yeah, it helps ranking good in YouTube.

But I don't think that it helps, to spam the description full of different keywords.

i always try to put my main keyword first in the title and first in the description and first in the tags. from what i seen it has helped me moved up the ranks on that keyword. With all that and 5k views a day i dominated on youtube for that keyword for 2 weeks. Now i have been pushed down the rankings to about 8 spots down

utube made some changes to there ranking system 1-2 weeks ago, they are adding alot of weight to fresh videos. so unless you build links to the video, its going to drop off the first page of its keywords after a while depending on how competitive the vertical is.