Say what you will about sarbox, but the fact that the public isn't able to get carried away in hype severely limits the size of a potential bubble.
Another data point to consider is the general internet savvy running around these days. Consider all the kids coming out of college these days that grew up with the Internet. A lot of them had cell phones when they were 10. Basically, all young people understand the Internet at a very natural level now; it's not just relegated to computer geeks and technology fetishists. This means a lot more ideas, and a lot better design, to say nothing of the improved tools we have today (REST vs SOAP, Rails vs ColdFusion, etc).
All that said, every bubble is different, and by definition happens because of what people aren't expecting. So I'd say there could definitely be a bubble brewing. Consider for instance, a future in which Facebook executes amazingly, but at the end of the day we discover that all that social activity is actually as worthless as Google hopes it is. The valuations are high because outcomes are unpredictable on this stuff, not due to irrational exuberance.
Another data point to consider is the general internet savvy running around these days. Consider all the kids coming out of college these days that grew up with the Internet. A lot of them had cell phones when they were 10. Basically, all young people understand the Internet at a very natural level now; it's not just relegated to computer geeks and technology fetishists. This means a lot more ideas, and a lot better design, to say nothing of the improved tools we have today (REST vs SOAP, Rails vs ColdFusion, etc).
All that said, every bubble is different, and by definition happens because of what people aren't expecting. So I'd say there could definitely be a bubble brewing. Consider for instance, a future in which Facebook executes amazingly, but at the end of the day we discover that all that social activity is actually as worthless as Google hopes it is. The valuations are high because outcomes are unpredictable on this stuff, not due to irrational exuberance.