One of the things I most enjoy about working in digital marketing is that there are no such things as certainties, and something you knew for sure yesterday may turn out to be complete rubbish tomorrow. Sometimes this can be really scary - any book you buy on the subject will be out-of-date the moment it's printed so you can't even rely on the traditional pillars of wisdom - but it can also be incredibly exciting.

An idea you had in the shower one morning can become a major plank of your marketing strategy the next day. A throw-away suggestion at a conference can ricochet round the blogosphere and be the hottest topic of debate within hours.

But that's all about theory, and the inconvenient truth about theory is that in practice it's only ever theoretical! How on earth can a marketer hope to cope with these ever-shifting ideas where there seems to be nothing concrete you can hold on to from one day to the next? Just how do we evaluate every new possibility against the myriad which we're already juggling? More to the point, how do we assess which things are going to change the world and which are going to fizzle out like a damp firework?

A breakthrough moment for me was when I finally realised that it's OK to experiment, and accepting that there are going to be things that don't work. For many marketers - indeed for many organisations - that's such a fundamental change to the paradigm that they just can't get their heads around it. Can it possibly be OK to gamble marketing budget knowing full well that the odds may not be that high? Should we push out that new piece of functionality into our software knowing that we might take it out again in a year because nobody needs it any more?

I believe the successful 21st-century enterprises will be the ones that are prepared to make this shift. I think there will be four key characteristics of these companies:

• They will look at every new possibility - whether that be a new technology like Twitter, or a phenomenon like user-generated content - and consider if they can make use of it. They probably won't jump on the bandwagon immediately, but they'll want to be in the early adopter phase of the classic uptake model.

• They won't ever do something just for the sake of it. If the new tool or practice doesn't fit with the brand, then they won't do anything until it does.

• They will evaluate everything carefully - not just in terms of ROI, but also in terms of how it's fitting in with what everyone else is doing. You never want to be the one still wearing brown when everyone else has decided that blue is actually the new black...

• Once something isn't working they'll drop it. This is, I think, the most crucial point. There's no point carrying on with a particular technology or idea if the world has now left it behind (unless of course, there's still an opportunity to use it distinctively).

Software tools such as Lyris HQ can really help with this. It's now a case of simply hitting one button to add a link so recipients of your email marketing can post your message to Facebook or Twitter - and it's then really easy to set up a segment in the Web analytics tool to see what sort of difference it's making to the Web site. Marketers can now easily experiment. What happens, for example, if you use the new Twitter feed on the Lyris HQ dashboard to identify people who talk frequently about your product or service, and then use email marketing to send them advance information ahead of everyone else?

Making it up as we go along is hard, but I believe that in this brave new world where nothing is certain anymore, it's our only hope. So let's throw caution to the wind and see what happens!