Computers need help

Computers are good at calculating, searching through data and doing other automated tasks. And they're fast doing so. They're much faster than any human doing these tasks.
That's why computers are used for assisting human beings performing certain tasks or, in some cases even replace the human being.

But don't despair. There are some tasks a computer can't do. And that's when a human being is needed to help the computer.
A computer can't easily recognise objects shown in a picture, something a human being does without any problems or hesitation. If you show a picture of 'a car by a lake on a sunny day' to a human, he or she will tell you it's a picture of a car with a lake in the background. It seems to be nice that day, because of the blue sky and the small clouds.
If you present the same picture to a computer, depending on the complexity of the algorithm being used, you well get an answer like : large blue surface with green and red area's, or maybe (if it's a very strong or specialised algorithm) red car on blue background. The algorithm probably won't be able to tell the difference between the blue of the sky and the blue of the lake.
The same is true for recognising text. A human viewer will recognise a word or some characters without difficulty, even if the characters are deformed, written through and over each other or when the colour of the letters and the background change. Computers can detect characters and words, but only if it knows the used font, if the contrast between the characters and the background is big enough (and constant) and if the characters are nicely aligned. And even then it makes mistakes. When the conditions are a bit less ideal, a computer has a very hard time recognising characters or words. Most likely it will fail to recognise anything at all.
That's the reason why so called CAPTCHA's are used to make sure a human is performing a task on a website, like registering on a forum, leaving a message on a blog or logging into a bank-account : a computer can't read the word in the image.
This way, automated algorithms that are used to flood forums with spam, are stopped (or delayed, as the algorithms to read captcha's are getting better).

But most of the time, computers (algorithms) are unable to recognise things a human does without effort. And that's were the human can help the computer. Computers are good at looking up information that's stored in a database. So if a database would be constructed linking the picture of the car with some keywords like 'car, blye sky, sunny day, lake, ...' the computer would 'know' what is on the picture. If the computer was asked to present a picture of a 'car' or even of 'car by a lake' it would filter through the database and come up with the picture of 'the car by the lake on a sunny day'.
A computer couldn't fill the database with keyword matching data, because it is unable to recognise what's on the picture, but a human could. Of course, it would be a very tedious task for a human being to look at every existing picture and tagging it with keywords. That's why a scientists came up with the idea to turn it into some sort of a game.
The concept is easy : two randomly picked people are paired and they are presented some pictures. They have to describe what's on the picture, using keywords or tags. If both people come up with the same keyword, they are granted some points and the next image is presented. The goal is to earn as much points, i.e. get as many matching keywords as possible, in a defined timeframe. The best scores are added to a highscore list.
The concept is simple, but effective. Google is using this 'game' to tag pictures found on the web, in order to return the best matching search results for images.

So, for now computers still need human assistance to perform certain tasks, like recognising characters, text, images or every day objects or understanding what a text or conversation is about. But maybe some day, computers could pass the Turing Test, and they would be able to 'recognise', 'understand' and maybe 'think' like humans do. But it seems that computing and Artificial Intelligence have a long way to go to be able to do that. Until then, computers still need help.