Got it. Question is how did ISNIT created a clickable link in comment?
The founders of this app, two guys from my town, are from a nearby village and they commute from their village to the town daily. They had to call and tell their parents that they reached their office safely. If they did not call the parents would get worried. Sude note: it is expected in India for grown children to live with their parents.
So they thought an app would help them save money and time. Also, this ensured their parents got a notification as soon as they reached their office.
If I am not wrong, Twitter is coming pretty soon. They also have something called Folwd http://folwd.com/ that allows you to keep your social profiles updated.
That was a common issue and requires a technological solution. This is why the links are now free for all. You can see all of the links for free and buy where you see the value.
The prices are known in advance. You can buy something for $X and sell it instantly at $X+Y. You make $Y profit out of which the site charges a percentage to give you the links to buy and sell the item.
It's not really me but my brother. The reason he is not doing it himself is because of his other startups. He does not have a lot of time and this way he can use some help by creating a win-win situation.