About the only reason I can think of for such research is that you are considering launching such a website yourself, or are working for someone who is. That's okay with me.
In that case you are asking the wrong questions.
Technical features aren't really what makes any lightweight backpacking website interesting or not. Content is. So good and frequently updated articles are important. A user community that is interesting and often well-informed and welcoming is important. Really that's why I am willing to subscribe to this site.
I don't know how much room there is for more lightweight backpacking web sites. Although if you really want to, I'd consider some degree of specialization or careful positioning to make your site different.
A couple of ideas on that positioning... There is a large population of active yet older people out there. A lot of them went backpacking in their younger days. Their kids are now in highskool or college. They probably aren't in as good a shape as when they were younger, though. Finding those people and giving them a gentle introduction to lightweight backpacking is a great idea. Bluntly, too, that is a crowd that will instincively be turned off by the distance-hiking crowd and probably has vehemently rejected the whole lightweight backpacking thing because they don't want to walk twenty-five or thirty miles in a day. Think about how many outdoor magazines really focus on newbies... Another idea is to have a very explicit regional focus to your site. That limits your market in one sense, but in another sense it becomes the place to go for detailed information on what works in that area... Still another idea is to focus almost exclusively on MYOG.
There are lots of other good ideas. Good ideas are cheap, really. You are closer to whatever problem it is you want to solve and can come up with your own answers. Chances are you will have more and better ideas than I can spoon-feed to you here.
Good luck in your research.