Traditionally an author finishes a book like this by telling you what to expect next. There's crystal ball gazing, there are words of wisdom. The thing is, technology moves quickly. Sometimes people go for a particular innovation, sometimes they don't.

Let me explain with an example. In the mid-1990s, not so long ago, Apple Computer was a computer company. It still is, but it's more now. In the late 1990s a company called Diamond started making a lot of noise (pun intended) about a gadget called the Diamond Rio. This was something they called an MP3 player. You could 'rip' music onto it and play it. Diamond didn't have the marketing clout that Apple had and it lacked the sheer design panache, so Apple picked up the idea, made it look like a neat product to own and an easier one to operate (reasoning that if people didn't have to learn it they'd just get on with it) and before very long Apple was a music machine store and seller of online tunes as well as a computer company. In the mid-1990s nobody would have seen this coming.

Likewise, even when blogging started (and putting your thoughts down on a website and bringing in links, pictures and anything else you might want sounded a mighty strange idea in theory before we'd all seen one), if someone had said you would soon be able to produce a sort of mini-blog, severely limited in character count, you'd have said they were crazy. Only I've just described Twitter. It sounds like an unlikely success story.

Outside the computer field there was the Filofax: remember that? Basically paper put into a nice folder. Everybody had one, but it was only a simple idea and hardly revolutionary. Ditto an innovation in the 1970s, Sony's Walkman. Everyone raved about it, but they'd had cassette players and earphones for ages. This wasn't so much new stuff as a new combination of existing stuff, hailed as a major breakthrough.

So here I am trying to work out what's going to be the next major wave of social networking. Tricky. Part of me wants to say it'll be something we've already seen and failed to recognize. Someone, somewhere, will spot what fits together and just do it.

There are a few pointers available if you care to look for them. I've adopted one in this book: the inclusion of Blellow in Chapter 3's listing of the great and the good in social media is a bit of a flier, since it's a very new company that started while I was writing this book. Whereas it might take off and become the business world's Twitter, equally it might not. If it doesn't, it won't be the technology that's wrong – sometimes the market does something unexpected; opts for VHS rather than Betamax, adopts a micro-blogging service that people who don't use think is a waste of time.

Look at what's happening in the search engine space. When I discussed search engine optimization I offered some pointers to what you might do to make your website search engine friendly. Half way through writing that chapter, Wolfram Alpha joined in the fray and received a huge amount of attention. It operates differently from its competition and offers answers rather than a set of links when you enter a question – or, more likely if your query isn't completely America-centric, it tells you it doesn't know what to do with the information you've entered. Is that going to change the nature of search engine behaviour? At this stage I can honestly say I have no idea. Google looks pretty unseatable as the lord of all searches at the moment, but 10 years ago so did AltaVista, Excite! and all the other directories people were using. In late 2008 another pretender to the search engine throne, Cuil.com, was launched; it hasn't yet caught light as a force in the market, but it may yet do so. Again, its founders say it behaves slightly differently from the other search engines available. Half of me says 'they would, wouldn't they', the other half says they may be right.

Then in the week of this book's deadline – no, really – Bing. Not the singer, not Matthew Perry's surname in Friends, not the PG Wodehouse character or the old email address of Stephen Fry who undoubtedly named himself after the Wodehouse character, but Microsoft's Bing. Launching to developers in the US, Bing is Microsoft's new approach to web searches. On the Bing.com website the company says: 'We took a new approach to go beyond search to build what we call a decision engine. With a powerful set of intuitive tools on top of a world-class search service, Bing will help you make smarter, faster decisions. We included features that deliver the best results, presented in a more organized way to simplify key tasks and help you make important decisions faster.'

I have no idea what that's going to add up to in practical terms, but it sounds as though it could be radical (or marketing waffle). And although Microsoft hasn't cracked the search engine market previously any more than Google has threatened Microsoft's market dominance in the office productivity suite market, you underestimate Bill Gates' marketing capacity at your peril. The rules on getting your site, blog or tweets noticed could be about to change, big time.

If that wasn't enough of a change, in the same week Google announced a project called Google Wave. Part of it is a development of email. Google describes it as email as if it had been invented now – so it's easier to put bits of media like video or sound in, and when two people emailing each other are both online it switches to instant messaging instead. It also contains event planning.

Why is this important to us? Because technology takes unexpected turns. Because Twitter wasn't planned as a social network tool in which people could talk to each other but as something people could use to make simple announcements. Google Wave will help people collaborate, it involves messaging and multimedia elements and it could – just could – take one of those unexpected turns and revolutionizing social media as a concept, if it can become one-to-many communication rather than simply one-to-one or collaboration within a workgroup.

Twitter burned slowly at first, but its ascent to dominance happened in the space of a few months. Is it going to continue as the leading social medium for so many people? Again, that's difficult to tell. The very simplicity that earned it so many plaudits and admirers could start to pall. A number of bloggers are starting to talk things up as the 'next Twitter', although whether they're serious or merely worried that they'll miss the next biggie when it does come along is anybody's guess. There will be repercussions from Facebook's acquisition of Friendfeed and Facebook has now released 'Facebook Lite'. Nobody knows how all of this will turn out.

All of this is my way of breaking it to you gently that I have no idea what the next major trend will be: whether you should be preparing for everyone abandoning Google and opting for Bing or Wolfram Alpha; whether Cuil.com will start directing you to Blellow instead of Twitter for your updates. I'd certainly guess that whatever mechanism evolves for bringing together your various different feeds will do well. Tweetdeck's bringing Facebook information in has been a good step in that direction, but it's an add-on rather than a new network or a revolutionary way of working.

Maybe there won't be a revolutionary new way of working. Maybe the answer to the question about what's coming next was buried in the first chapter of this book, in which I spoke about my early days networking socially with Cix, CompuServe, AOL and other facilities like those. Perhaps things haven't changed as radically as all that. Perhaps there's one constant that we shouldn't overlook in all of these social networks: people.

People will keep communicating. Ever since the first magazine launched its first letters page, people have wanted to make their presence felt and feed back into things when they are presented with information or offered a viewpoint. We react. All that's changed is that we can all make our voices heard rather than only one or two of us on a letters page that's limited by space and the editor's choice. And it can be an ongoing conversation rather than a one-way monologue (even a letters page offers only the briefest of opportunities to make one comment).

People will harness whatever technology they can in order to communicate. Twitter wasn't about communicating at first, it was about making announcements. The Internet itself was largely a series of brochures initially, then blogs came along and turned it into a debating ground. Now it feels wrong when a news story online hasn't got a space for comments.

It's this element of which you can take advantage. People want to engage with each other whether they're online or not. They may well want to engage with you.

Look closely at the product or service you offer and think it through. Look at the customers you have and the ones you want to gain. Is social media right for you? If so, then by all means look through Chapter 3 and decide which of the various offerings is best for you and business plan it in as in Chapter 7. Also look on the web. Some of the players I've discussed might conceivably have gone away.

However, the principle of people wanting to engage somehow will not change. The name on the tin might be Twitter, or Facebook, or Blellow, or something completely different, but you can be certain the idea will still be around. And the planning, the resources, the motivation of an online community, the balance between spending time on this compared to the likely return on your investment: all these stay the same.

These are the skills you'll need to make social networking work for you. Remember the 'social' bit, so no hard sell: think Tupperware Party rather than door-to-door hawking. Remember to give people a reason to come back to you even if they're not spending money each time. Remember an engagement is two-way, but also remember you've got a living to make and you're not doing this as a hobby, it's a business, so you do need a financial return of some sort.

Get social networking right with the right business and you should start to see results in the form of hard cash arriving very quickly. You'll also see people enthused and recommending your product and service without your having to pay for massive extra publicity. Make it part of the mix – don't mistake it for a substitute for traditional marketing but part of it, a new facet – and it will be incredibly cost-effective.

Good luck!