"The opinion social network Simply collect, express and make sense of opinions" Looks very like Quora to me, and since it doesn't appear to offer anything that Quora doesn't, that's the end of my interest I'm afraid. The main difference is the polls aspect, which is great but limited.
I'm always wary when I see phrases such as 'let's sort out the net' because it shows such a depth of misunderstanding it's scary. However, moving on from that, sortpage is claiming that it's going to be able to do just that - with our help, of course. It's an alpha search engine, and at the moment is just concentrating on Apple data, but the idea is that people join and add their own favourite pages (while promoting themselves in the process) to provide more data. Guys - this simply isn't going to work. Not enough people care, and you've already got more than enough data with something like Delicious to play with. It's a great idea, very worthy, and won't be here in 6 months.
True Knowledge "is a pioneer in a new class of search technology that allows you to ask questions on
the web, just as if you were talking to another human being.
Rather than trying to guess keywords to find the information you are looking for, you simply
ask True Knowledge the question you want to ask. Our answer engine does not simply
guess at relevant web pages, but rather understands the meaning behind your question:
drawing inferences and conclusions when needed to find the answer you are looking for. True
Knowledge is tapping subject matter experts around the globe to build its information
repository - bringing together the benefits of machine-driven automation and people-driven
It's clearly best at factual data - how many feet is 60 inches, population of London and so on. It tends to fail, not surprisingly with touchy feely questions, such as 'which is better, a or b?' The answers it gives are reasonable. A search for 'what is twitter' gives straight forward functional information, such as business type, website, email address, wikipedia page and so on. Users can log in and give their own answers as wel, and these can be voted up or down. There are also links to other sites, such as ChaCha, Wikianswers, Answerbag and so on.
I prefer Trueknowledge to ChaCha - the answers are more indepth and factually useful. I asked the question "What is the population of London?" and ChaCha simply said 7,518,000 without any details as to where it got that information. Trueknowledge gave the answer 7,556,900 and linked to london.gov.uk and Wikipedia. This was closer to the figures mentioned on the Mayor of London's site than the ChaCha offering.
However, these are not the only engines that are in this area. The obvious other one which is in the news at the moment is Aardvark which I've used for a long time. It's a nice resource since it allows users to register and list what subject areas they know about. They can also ask questions - Aardvark will then route the question to someone it thinks can answer the question. I've linked mine up to my Google account, and perhaps once a day it pops up in my chat box with a question that I can try and answer or not as I feel inclined. The strength/weakness of the service is of course that it depends on the ability of the person asking the question, so rather than asking factual questions, Aardvark is the place that I'd go for the 'is a or b better?' I've asked questions about vegetarian food and game software, and answered a wide variety, mostly in the internet area.
Of course, if you don't like any of those, you could try Mahalo. I have a personal bias here in that I don't like Mahalo. The ask question element is right at the top of the screen, so you merrily ask the question, categorise it and only then do you get prompted to log in or create an account. I tried searching Mahalo for my London population question and got no answers at all. However, when I asked the question on the home page I had results from Wikipedia and a school website page. Admittedly there were links to news information, images and videos. I had to hunt around in order to get somewhere.
So - a few different engines to try. None of them perfect, but this is the internet, what else can you expect?