- Facebook will not be displaced by another social network. It will IPO some time in the next two years.

- Twitter will become profitable, but not as much as some expect. It will be less profitable than Facebook, and may sell to another company.

- Microsoft will not have gone anywhere, though it will have shrunk and may have evolved into a consultancy company on the lines of IBM. Many businesses on the Mircosoft stack will remain on it. Although the desktop market will shrink, perhaps considerably between 2015 and 2020, desktops will still be sold to hardcore PC gamers and in the third world, and Windows will remain the OS of choice. Laptops will become the standard computer, and Windows will also retain the majority market share, though OS X, Linux and Chrome OS will all gain here.

- Internet Explorer will shrink, but won't go away. IE6 will hang around for a few years, but may die very rapidly in workplaces when some killer enterprise web application stops supporting it. It will remain widespread in East Asia, at least as far as 2015. Now that Google is advertising Chrome on billboards here in the UK, all that can be safely predicted about the browser market is that it'll be extremely competitive.

- Chrome OS or a similar operating system that relies on web access may grow extremely slowly at first, before rapidly gaining share amongst certain market segments. It will be most successful in places like cities that grant free municipial wifi access.

- Mobile phones won't replace computers, but increasing penetration amongst the poorest in developing countries, and increasingly capable handsets in developed countries (and developing countries) will make them a colossal juggernaut. Many of the really big changes, especially social changes, will be caused by mobiles.

- For any definition of 'success', there will be more tech startups reaching that level in the 2010s than in the 2000s. For example, there will be more than four startups of Youtube/Facebook/Twitter/Zynga proportions.

- In addition, at least one of the 'big' startups of the second half of the decade will have been possible with 2009 technology. By this I mean that people will still be discovering new potential for browser-based web applications built with current client-side technologies, which will remain ubiquitous, although new alternatives will appear.

- It will be an even better time to start a startup in 2020 than it is now. One of the key drivers of ease-of-starting-up-ness will not be new technology, but new platforms - like Facebook and viral marketing, but better; or that solve other problems like micropayments, customer development, retention, and so on.

- Hence, starting up will become a more attractive career option, though well-meaning family will still say "at least finish your degree first".

- As Moore's Law marches on, dynamic languages that are even slower than Ruby are likely to catch on. They may be to Ruby what Ruby is to Java, trading even more programmer time for CPU time.

- Having said that, Moore's law will at least hiccup and may stop altogether in the middle of the decade, as semiconductor feature widths drop below 11nm. Since this will likely encourage investment in quantum computing and nanotechnology, by 2020 we might be seeing something faster than Moore's Law.

- An international deal, of the kind that was aimed for at Copenhagen, will be reached over the next five years, though it might not be far-reaching enough to limit warming to 2 degrees in the long-term. (Despite the failure of the Copenhagen talks, it appears that world leaders almost universally recognize the need to take action over man-made climate change, though the various political problems will remain hard problems). China may not be part of such a deal, though the US likely will. Environmental disasters will begin to increase through the decade, as will disasters that are probably not caused by anthropogenic global warming but will be blamed by it anyway; this will provoke more of a push for action.

- Increasing fuel prices, and green taxes or incentives, will mean large shops will begin to replaced by warehouses, as traditional retail gives way to home delivery.

- China will not become a democracy, or even make moves in that direction. However the rule of law will strengthen, and some civil liberties will increase. Internet crackdowns will continue, and may increase in severity, and will still be rationalized by porn.

- Despite multiple new fads that purport to make software development ten times faster and error-free, it will remain a hard problem.

- You still won't be able to talk to your fridge, and gesture-based HCI will remain a fun gimmick.

- Virtual worlds like Second Life will remain niche, but World of Warcraft will pass 20 million users and a Facebook game or similar will pass 200 million users.

- The next big thing will be something totally unknown and unpredictable now, as user-generated content and social networking were in 1999. However, when it does appear, various 'experts' on it will spring from nowhere to lecture us all about it. It will still be really cool, though.

I am actually going to save a copy of this; although they all seem perfectly reasonable to me, from an objective standpoint I'm probably laughably wrong on at least 2/3 of them, and it'll be interesting to look back to see which ones they were.