Plenty of people have taken a run at the whole Web 2.0 thing — the question of whether the term is a load of bollocks, a useful concept or just marketing hype — but if anyone should have some perspective on it, it’s Marc Andreesen. After all, he’s the guy who gave us the first browser when he was still a university student (I can still remember when I first used Mosaic), and then went on to form Netscape, arguably the first Web company.

The only other guy who might have even more perspective on the whole Web 2.0 mess is Sir Tim Berners-Lee, who invented the Web in the first place, and who has made his thoughts known in a couple of different places, including a podcast with IBM (transcript here) — and in an interview with yours truly from the W3 symposium in Banff recently. In effect, Tim (he says that anyone who uses the Sir has to buy a round of drinks) and Marc both agree that what we call Web 2.0 is really just the Web as it was meant to be. In other words, all of that interactivity and so on is just the way things were supposed to work in the first place. It’s just easier now.

As Marc points out, it’s telling that even Tim O’Reilly — the guy who came up with the term in the first place, in order to sell the idea of a conference on the topic (which he famously trademarked, causing a minor blog storm) — has a lot of trouble defining exactly what Web 2.0 means. Dave “Mc500 Hats” McClure takes his own run at doing it in a comment on Andreesen’s blog, but doesn’t really fare much better (although it’s shorter).

Does Web 2.0 refer to tools like Ajax? Is it just a term that means interactivity? Is it an approach to design? Does it mean community? Is it a load of bollocks, a useful concept, or marketing hype? That answer to all of those questions — and more — is “Yes.” Web 2.0 means everything, and nothing.

My friend Paul Kedrosky — who unfortunately wasn’t able to make it to mesh last week, and therefore wasn’t able to share any of his wisdom in person — is right to point us towards a great post from Marc Andreesen about the non-bubblishness of the current tech bubble.

The Netscape co-founder has a long and very worthwhile analysis of why we so often see bubbles. which are actually extremely rare (this NYT story has some thoughts on that as well), and also notes several things about the current tech “bubble” that make it different from the first one — and he is ideally placed to have some perspective on that. Among other things, he notes that there are far fewer tech IPOs now (and therefore less hype and potential for financial disaster) and also that:

– It is far cheaper to start an Internet business today than it was in the late 90′s.

– The market for Internet businesses today is much larger than it was in the late 90′s.

– Business models for Internet businesses today are much more solid than they were in the late 90′s.

This is a logical consequence of time passing, technology getting more broadly adopted, and the Internet going mainstream as a consumer phenomenon.

Andreesen says that he believes it is “about 10 times cheaper to start an Internet business today than it was in the late 90′s, due to commodity hardware, open source software, modern programming technologies, cheap bandwidth, the rise of third-party ad networks, and other infrastructure factors. And the market size for a new Internet business is about 10 times bigger than it was in the late 90′s.”