I hate to state the obvious, but you can always not open the thread if the contents are not to your taste.
To Loote's point, each of those threads he mentioned serve to bring people together in their own unique ways. I completely agree with his take. I think this trend in Sajha is a reflection of a larger trend on the internet as seen with the popularity of sites like Myspace and Facebook all of which, like these threads on Sajha, seek to connect people with common interests in whatever ways the users please.
While the organizing principle of content on Sajha is still of a bulletin board nature which was very popular at one time, the actual content itself is much more on the lines of what you see in the rest of the social internet : blogging and sharing items and ideas of common interest to people.
Bottom line: nothing extraordinary going on here, things are just moving with the times. NatankiLand, Chautari, Another Song, Song Dedication, Sooo Happy ..., NFL Playoffs, A sher a day, etc (I know I missed a few) are all just another sign of the times.
Just my thoughts.