Yes, absolutely. This is an obvious realisation when you think about point 3, promotion. It's really difficult to promote a site that does a little bit of everything. You can't explain its appeal succinctly and clearly. Once you try to promote your site, it becomes obvious that covering several vastly different topics doesn't work.
FWIW the site used to be 3 separate sites for the first 3.5 years:
* Tech/Video Games site
* Humor site
* Programming site
and none of them did particularly well on their own. It was also mentally draining for me to try and manage 3 separate communities, so I combined them all.
Probably not the best decision now that I read your replies though.
