What it is: a large internet business conference with hundreds of web start-ups and thousands of executives, most of whom have flown in from the US or Europe.
What it's not: a tech gadget fest. There are no iPad, smartphone or Xbox booths on display here. Nor do big manufacturers use it to announce new products. It is very different from hardware or gaming conferences like the giant Consumer Electronics Show of Las Vegas.
Who it's for: tech start-ups, tech investors and those hoping to make money out of both. While the core attraction remains start-ups and venture capitalists, the Web Summit is now a magnet for marketing, legal and financial services firms hoping to get new clients.
Who it's not for: casual tech geeks. Tickets cost around €500. If you're there, you probably want to have a good business reason for it.
Do any jobs come out of it? Yes. Yesterday, there were multiple job and funding announcements made to coincide with the Web Summit. Aside from the new jobs, several Irish start-up companies, such as Trustev and CurrencyFair, announced multi-million euro founding rounds.
The 42-year-old has reportedly been the model used for framing the character of the movie superhero, Iron Man.
Other highlights: Taoiseach Enda Kenny ringing the opening bell yesterday for the Nasdaq Exchange, the first time this has happened outside the US.