These things rather speak for themselves.

Typical domestic internet access speed
1999: 56kbps
2009: 10Mbps

Time to download a 4Mb file (approximate)
1999: 10 minutes
2009: 4 seconds

Typical internet service costs
1999: £49.99/month anytime access, or 1-4p/min
2009: £10/month

Browser Market Share (approximate)
1999: Internet Explorer 75%, Netscape Navigator 25%
2009: Internet Explorer 60%, Firefox 30%, others 10%
(note Internet Explorer usage peaked in 2004 at 95%)

Search Engine Usage (approximate)
1999: Yahoo 40%, AltaVista 12%, Lycos 5%, Excite 4%
2000: Google 95%, Bing 2%, Yahoo 2%

UK Internet Advertising Spending
1999: £51 million
2009: £3,500 million (forecast)

Google Advertising Revenue
1999: 0
2009: US$ 22 billion

Ten Things Which Weren’t Around In 1999
Google (unless you were a real nerd!)
MP3 players (as above!)
Broadband internet access at home
Internet access – or cameras – on mobile phones
Writing your own DVDs
Windows 2000, ME, XP, Vista, 7, Mac OS X, etc
Facebook, YouTube, Twitter
AdWords
Wikipedia
Blogs

I think the point of all this is to say: if all this happened in what was the first full decade of the internet for most of the world, just what is going to happen in the next? I can’t wait to look back on this in ten years’ time, and see which trends continued at these sorts of rates. Will our web access speeds rise to 2Gb/s? Will internet advertising’s market share carry on past the current 25% to 50% or even more? Will we even be able to distinguish between radio, TV and the internet any longer? Your guess is as good as mine.