Yahoo's launch at Mobile World Congress of oneConnect, the communications service for its upcoming Yahoo Go 3.0 mobile client, looks like nothing short of a cellphone land-grab.

For many users, oneConnect will be the only service they need on their mobile. Due out this Spring, it pulls together your email, text messages, IM services, social networking and heavens knows what else, all in a single client that - from the demos, at least - looks an order of magnitude easier to use than Yahoo's previous attempts.

In particular, it's not tied to Yahoo's own services. It also retrieves messages from MSN, AOL, Googlemail and others, and is extensible via widgets - the company demo'd one which adds access to Microsoft Exchange email.

It can connect to a wide variety of social networking services too, such as MySpace, FaceBook and LinkedIn, pulling in status updates (the "Fred is... enjoying Barcelona" sort of thing), notifications of photo uploads and the like.

On top of that, if you allow it to be made public (you'll be invisible by default, says Yahoo) it can include your location, derived from which cell tower you're logged onto, the GPS receiver in your device if there is one, and in the future near-field comms such as Bluetooth.

So not only can you see what your contacts have been up to, but you can see where they are - and get proximity alerts, so you can message them to meet for coffee, or whatever.

How well it all worked together looked impressive in the demo. For example, you can drill down to a contact and see how you're linked to them, the messages you've exchanged with them, or a list of their various status messages.

There's presence data too of course, if they're logged on to IM. You can even - shock, horror! - phone and speak to them, all from within the one program.

My question is this: for the average user, whether consumer or business, what do you need on your phone apart from this lot? Don't forget it's part of Yahoo Go, so there's also access to newsfeeds, weather forecasts, driving directions and so on in there.

And if you don't need anything else, all the stuff that's pre-installed on your phone is redundant. Goodbye Symbian, hasta la vista Windows Mobile - and ¡Hola! Yphone.