I'm now on a score of about 47 booked-in meetings, receptions & other events next week in Barcelona. It's not quite a statistically-significant sample, but I'll take a punt on what the hot topics are going to be:
a) Femtocells. Not exactly new, but then nobody seemed to know what I was talking about last year whever I mentioned them. (Incidentally, I've been wading through the NGMN's white paper on future cellular technologies, and picos/indoor solutions got an honourable mention, so expect to see them designed-in to future mobile architectures upfront, rather than added on as an afterthought).
b) Social networking from your mobile. This seems to be the great hope of anyone trying to grow revenues from their mobile software client business - uploading pics & videos from your phone to your blog. Everyone's at it: OS companies, UI companies, on-device portal companies, remote-backup companies, photo application providers and so on. I bet there will be dozens of handset software firms that have added a "social networking module" to whatever they've been trying to sell for the last few years. So if you're thinking of joining the party - stop, you're too late, it's saturated already.
c) HSUPA - yep, high-speed uplink radio technology, just when you want to upload all your pics to Flickr and MySpace. Should make for better VoIP over cellular, too.
d) VCC - also around last year in "pre" versions, but a bit more real this time around. Expect to see a few cool-looking dual-mode WiFi/cellular SIP-based phones as well. I quite liked E28's devices when I met them the other week.
e) A million and one pointless messaging solutions. Look guys, we're just not interested. The world is either SMS (mobile operators) or IM (Internet players). All the rest is a distraction, with maybe a few interesting niches that a few % of people might play with. Both SMS and IM have such huge & loyal user bases that I expect to see neither mobile companies succeed in IM, nor IM companies succeed in dislodging SMS. In the longterm we'll see some tectonic-speed shifts, but for now the main outcomes are (a) price cannibalisation on SMS, and (b) IM players forced to interoperate & sometimes collaborate with operators. (And yes, I know that US SMS prices have risen recently. Strangling a golden goose is always one way to force a transition, I suppose).
f) A million and two pointless mobile search solutions. Especially the anti-Google operator consortium one. Yawn.