Well, after a few days spent on your website, I think I'm beginning to get a better understanding of its potential.
Here are some ideas/opinions of mine... And I invite other users to use this topic to share their own ideas and opinions after spending a few days on OpiWiki.
1- This very section, Meta, is almost hidden. You have to scroll down at the very bottom of the page to find it. And the link isn't too welcoming either. I think it partly explains why you get so little views and comments in here. I think you need much more feedback - from a lot of users - in order to get a wider view of how people see OpiWiki. You should find a way to make it more visible for casual users because you also need their opinion, since they will form the majority of your users in the future.
2- The categories are just a tiny bit messy. For example, "entertainment" does not include "video games". Personally, I believe it should fit in the entertainment category. I think you have a very good example of how to classify categories here: en.wikipedia.org/wiki/Portal:Contents/Portals
Of course, right now, the categories don't seem too bad as they are now, but that's just because OpiWiki still lacks items/pages. If your website ever becomes very popular, you'll be swarmed with rankings, items, polls, etc. daily and the mess will get bigger and bigger as time goes by. It might not be hard for you to switch and arrange categories, but your users need to find what they are looking for as fast as possible in order to be satisfied. That's how internet goes today. The category menu must look as simple as possible. A drop down menu could be handy.
3- The "Other" category... You have to find a way to eradicate it ASAP. I think it's proof that the categories need to be worked on. It shouldn't exist. It has the potential of harboring all sorts of topics that could fit elsewhere, and it will just be painful to browse at some point. Right now, it's not very popular, but that's just because your user base is smarter than the average person. :P There are a lot of teachers, smart and wise people who are old or mature enough to know where to post their stuff. But it might change in the future, whether we like it or not. :P
4- I hate to be the one to say this but... Netik, the little robot, should be disassembled... He looks too much like the Android robot. But you should stick with the initial essence of Netik. You need a mascot who looks smart, useful, fast, elegant, perfect. You still need a robot, or something as good as a robot. An alien or a scientist could be good too. Your mascot has to give the impression that it can do anything. Just like your website.
5- On my first day impression, I said I wasn't sure how you could make this website profitable. Well, I thought of one way. Use ads according to the different categories. Example, whenever a user visits the sports category, there could be sport ads. With video games, they'd get video game ads, etc..
6- Have you thought of presenting OpiWiki on a website such as Kickstarter?
7- If you search for an item that wasn't created yet, you will be told that there are no results. Could it be possible to invite the person to create the said item? Maybe you'd get more items that way.
8- Talking about items... I think they are the key to your website's success. People want to look for something specific most of the time. Items can deliver what they are looking for. At some point, when your website has a solid item database, all the polls and discussions will link to an existing item. I think items and rankings will truly be the reason why your website will become huge, because people look for ratings whenever they use Metacritic, Rotten tomatoes, IMDB, IGN, etc.. They want to see what people think of this and that, and they want to debate about it too. The polls and discussions should ultimately become secondary to the items. Right now, I feel like the items are somewhat left behind, stuck on a shelf. That's why I chose to focus on them.
9- One thing I'd like to see in the rankings would be to be able to rate all the items on the ranking page without having to click on each and every single item to do it on their own page. Of course, this could also lead to excessive ratings by people who might not even know what they are rating. In that case, they'd just do it for the "points" in their profile. But, on the other hand, you'd get more votes for every item since it would be easier and faster for (the nice) users.
10- The "candidates" lists - whenever an item has no votes yet. It's kinda left in the dark. I didn't notice its existence until today. Maybe you could keep that list where it is, but also include the candidates at the end of the rankings' lists. You could also add tiny thumbnails (ex: 50x50 pixels ) of the candidates somewhere on the main rankings' pages. Maybe people would then see them more easily and recognize some people/things they know and will be interested in rating them as well. Otherwise, I think they could remain candidates for a long long time.
11- Finally, right now you have "ads" that lead to certain items. It would be cool if some could lead to rankings as well. I haven't seen any yet.