Not a Twit!

This article is very short, so first, please listen to the news article: Click here to listen

Questions:
1) What is meant by 'It's a big bet' near the end of the report?
2) According to the article, what is the reason for its shares being one of the most expensive new issues ever?
3) What is your image of why twitter is so popular around the world?

If you couldn't catch everything from listening, then please see the article here.
You can see the full BBC article here.

Example answers:
1)'It's a big bet' or 'it's a good bet' means it's fairly sure - so much so that one could put a bet on it and have a high chance of winning.
2)The share value is measured relative to revenue - and Twitter has no profit, so the shares are rated very high.
3)Many people like Twitter compared to blogs or Facebook because it's so easy and quick both to check other people's comments and to make comments. The limited number of characters seems very restrictive at first, but this has been its strong point. The short messages also help to make it easy to follow many people without the timeline getting too crowded.