What's the legal definition of browsing?

I see that O2 UK has just revamped its data 'bolt-on' tariffs, towards a pseudo-flatrate offer comparable with T-Mobile Web'n'Walk and others at £7.50 for 200MB per month. About time, although as it'll come as no surprise that they're retaining the usual 10000% over-pricing on roaming at £6/MB - or £15/MB on prepay. (Yes, OK, there is the rather laughable 'data abroad' bundle of 10MB/month roaming for a commitment of £10/month. Bargain.)

In common with most of these, it also has the usual backside-covering 'fair use' terms and conditions.

"Permitted Uses of theO2 Web Bolt On are uses of your SIM Card within a handheld mobile device for the purposes of Internet Browsing and email only. Any other use of the O2 Web Bolt On will not be a Permitted Use, including but not limited to:

Use with Data Cards or Modems;
Instant Messaging,
IP Telephony,
Point 2 Point file sharing and file transfer,
VoIP (e.g. Skype™),
Video and TV streaming,
Slingboxes; and
Use in conjunction with routers."

But tell me... what exactly is the legal definition of 'browsing'? If I visit a website that happens to have embedded Flash animation or video streaming - like http://blueroom.o2.co.uk/2007/the-o2/sugababes-gallery.jsp for example, am I falling foul of the T's and C's? What about the messaging functions on FaceBook? Are they 'instant' or does that mean where there's a separate pop-up IM window? Can I use an open chatroom but not a private message window? What happens if there are only 2 people in a private chatroom? What if it's embedded in JavaScript on some new Web 2.0 social networking website? What if Skype develops a plug-in app that appears on certain Facebook or eBay web pages?

And I fear that using the Internet without somehow being 'in conjunction with routers' may be a little tricky. Especially if O2 launches a femtocell / home gateway.

You get my point. 'Hard' definitions don't work very well with traditional Internet applications, and are even worse with AJAX, Widgets and Mashups. Yes, of course I know what the T's and C's mean in spirit, even if it is mean-spirited.

Put simply, I don't think any of this stacks up, apart from instilling 'fear, uncertainty and doubt'. I'm not picking on O2 specifically here, most of the other operators, with the notable exception of 3's X-series, do something pretty similar. Essentially they're writing themselves a 'get out of jail free' card.

"Fair" in 'fair use' seems to mean "uncompetitive with anything else we do already or might do in the future". "That is, if it is used by enough people that we decide to take some action." So "Unfair" = "Competing effectively".

The strange thing is that they haven't applied equivalent rules to ordinary voice calls. Surely, taking this to its logical conclusion, it's not 'fair use' of my O2 voice minutes if I use them to call Vodafone's sales department, or Orange's analyst relations team?

Personally, I don't think these onerous but vague and sometimes threatening data plan T's & C's will stand up for much longer - except in the case of really bandwidth-heavy or malicious apps which can threaten network integrity. I expect most operators to have quietly moved away from these positions by the end of 2008.