Why do you think Gintama is unpopular?

Two reasons:

1. The first season is slow. A lot is due to character introduction, exposition, etc. So there are a lot of people who just give up.

2. It's very Japanese. There are a lot of cultural references that most non-Japanese will not get. Hence all of the translator's notes. Of course, all of the references basically tell me what I need to watch to get my basic otaku skills down.

Those who fault the potty humor or the maturity level must remember how popular Family Guy and South Park are in America. Some also blame the "serious" portions of the show, but I believe that those arcs add contrast and awesome action. I'll never complain about seeing Gin-san win a fight ^_^

It is because the first episode is very confusing to people and if your not bored outta your mind and found it quite funny (like me) then you will continue to watch, but if your confused and don't get it you wont continue to watch. It also depends on your sense of humor.

unpopular?? hell no

Excuse me, but since when do "unpopular" series get over 200 episodes?

i guess its not that popular in countires other than Japan b/c it doeant really have a story line like the blockbuster mandgas, Bleach and Naruto, its more like a collection of humorous and satirical episodes. I like that aspect of it, but I guess some ppl prefer having a solid plot line. another factor is the heavy reference to Japanese culture...I wish my friends appreciate GinTama too...

Gintama is popular :/ GINTAMA IS THE BEST

gintama is awesome! but i guess its not as popular as other anime cause it isn't your conventional shounen manga and isnt filled with battle scenes every episode.

Why is not popular outside of Japan you mean... 'cos there is quite massive from what I've heard, and to me that was done very deliberately by Sorachi. I've got the feeling that he's quite nationalist and rather anti-foreign, kinda like Zura really
The signs are all there: very strong japanese culture references, even mentions of old fashion TV presenters that no one in the Western world would know, jokes and puns that in most cases can hardly be translated, big slices of Japan's history (before watching Gintama I had no idea that Tokyo used to be called Edo and never heard of the Shinsengumi) and the vile Amanto are obviously the people from the West who came to conquer the Country and force their own way of living. If you notice there's no mention of other nations at all, is like if Japan is the only country of the planet and all the other races are aliens. What Sorachi wanted to do was probably create something very exclusive for people in Japan and whoever else is strongly into it, but also off-putting for anyone who's not a real manga/anime fan.

... Except for the American pop culture references (Star Wars, Will Smith and so on and so forth), Takatin, the Christmas Episodes (We're in Texas now!?) and the part where everyone'll rattle off something in English from time to time...

And as for puns, most wordplay doesn't translate out of its native language very well. If you're gonna be punny, it will only really be funny in one language (although Sorachi's been known to crack some puns in English as well).

Wasn't a criticism, totally the opposite.

I was just pointing out where that argument falls apart. X)

Gintama's first 20-ish episodes are kinda slow paced, as they are presenting you each character from the main cast, their backgrounds and quirks. Then we start the death note's parody. As we already know all quirks, Gintama shines as a great comedy.

And we fall right into Benizakura arc. Gintama activates GOD MODE!

Concerning the Sorachi is a nationalist theory :

It's a quite interesting theory, but you forget that the series is set in the period where foreigners came to japan. When you look at other stuff from sorachi, you don't get that feeling all too much (his one-shots and stuff).
Also, if he really was a nationalist he would not have missed the chance on ripping the US and Eu translated licensed manga. (or maybe he is a very greedy nationalist? *shrug)

Maybe I didn't express the concept very well. But I still think that he wanted to produce something quite exclusive for japanese audience and other people who are REALLY INTO japanese culture, and wouldn't easily be exported. A niche manga/anime accessible to a selected public basically. But then again that's just an impression, I could be wrong.

It's not aimed exclusively at a Japanese audience; rather, it's aimed at the Weekly Shonen Jump audience who happen to be almost entirely Japanese, hence the large amounts of Japanese pop culture included. But there are a lot of gags that lots of Jump readers may not get.