Keep in mind I would rather not predict the obvious.
1. Twitter Manages to Complete 2010 With No Major Hacking or Security IncidentsDespite a strong 2009 that saw the microblogging service graduate from the geeks to more mainstream appeal, Twitter remained plagued by a number of uptime issues and some extremely visible hacking and security incidents that led to slowness and downtime. As part of the company's maturation process, Twitter will build the personnel and infrastructure necessary to withstand such future attacks, and 2010 will go major incident free. There may be some slowness, but no outages via the dark corners of the Web.
2. Seeing Android and iPhone, Windows Mobile Will Aim for Parity, and Fail
Microsoft, jealous at all the consumer and media attention around the iPhone, and now Android, will try to remain relevant, launching a new version of Windows Mobile, and hyping its own apps, just like they did when they launched the Palm PC line (later Pocket PC) following the PDA's rise to power. Their approach will not be seen as comparable to Android or iPhone and will not change their market share in a positive way.
3. Apple Will End Exclusivity With AT&T, Adding T-Mobile and Verizon
With AT&T being a massive black eye for Apple's iPhone in the US, the company will finally end exclusivity with the telecommunications carrier, and strike deals with both T-Mobile and Verizon. Consumers will be able to switch carriers and keep their numbers. Unsurprisingly, users may find that those networks aren't perfect either.
4. Facebook Will Announce a Migration Plan for FriendFeed Users
The mystery around Facebook's plan for FriendFeed will become clear in the first half of 2009, as not only does the company improve its network with FriendFeed-like elements, but existing users of FriendFeed will be given guidance on how the two networks can converge, while protecting their existing content and contacts.
5. Google Wave Will Exit 2010 Still In Beta
While Google Wave will continue to improve and may open up to all visitors, without requiring invites, the product will still be seen as experimental, and will not shed its beta tag, keeping it through the end of the year, much like GMail and other products from Mountain View before it.
6. Facebook, Zynga, LinkedIn Will All Go Public
After a dearth of IPO activity in the last two years, 2010 will see a resurgence, especially from Silicon Valley VCs, who are eager to make profits to help assuage the wounds of losses from the last few years. Facebook and LinkedIn will be among the larger IPOs, with Zynga also filing, and other smaller companies following suit.
Twitter may file, but will not be public by the end of 2010.
7. Chrome OS Netbooks Will Be Available from Major Retailers
Google's Chrome OS will reach a maturity level that it will be sold on netbooks alongside more traditional offerings from major retailers including Best Buy.
8. Many Social Media Experts Will Launch Mediocre Agencies
Many of the self-proclaimed social media experts will leave their corporate day jobs and strike it out on their own, looking to convert the world to Twitter and Facebook fan pages. A good number of them will find that the world of business relies a lot more on revenue than it does on retweets and @replies, and may walk away disappointed.
9. Google, Facebook and Apple Will All Make $1B+ Acquisitions
In addition to the new public market activity, acquisitions will again become trendy. Google and Apple will make full use of their growing cash hordes, and will make at least one ten-figure transaction in the year. Facebook, fresh off its cash raised from the IPO, will do the same, largely in stock.
10. The Real-Time Search Market Will Consolidate
One or more of the active dedicated real-time search companies will find differentiation difficult, especially with Google, Bing, Twitter Search and others participating. The trailing market share participant will either merge with an existing site, will close down, or look for a low-budget buyer.