While Mobile World Congress watchers originally thought SDN and NFV would be the biggest topics of discussion at the show, 5G barely snuck by as the most attention-grabbing topic at the year's biggest mobile bash.

Our recent poll on MWC's hottest topics attracted a record 1,720 responses (and growing by the minute), 820 of which came during the show week as people had a chance to see what was grabbing headlines. (See Hola, MWC#15 and Poll: NFV/SDN, 5G & IoT to Dominate MWC.)

Of the 900 who voted prior to the show, 19% thought SDN/NFV would be the biggest topic during it, followed by 5G at 16% and the Internet of Things at 15%. Post-show, those numbers came to 19% for 5G, 18% for SDN and NFV and 14% for IoT as an additional 820 people weighed in. All of the other topics were in the single digits.

Check out the chart to see how the votes stacked up before the show -- with 900 poll takers -- and after when 1,720 of you weighed in.

Figure 1:

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MWC is such a huge show -- 90,000 people traversed the Fira this year -- that it's hard to pick just one or two dominant themes. It all depends on which hall you spent your time in and whom you met up with. That said, from where I sat (in the press room) and stood (halls 2 through 8.5), 5G was definitely the biggest trend. In fact, as our respondents suggested, SDN and NFV didn't come up much as we expected, although a number of operators and vendors talked more generally about their plans for virtualization. (See SoftBank Bringing Self-Learning Tools to Sprint, CEO Chat With Axel Clauberg, Deutsche Telekom and CEO Chat With Simone Battiferri, Telecom Italia.)

Instead, pontificating on 5G -- it's use cases, business models, challenges and more -- dominated a lot of attention on the show floor. (See Growth of the 5G Ecosystem, NGMN Chairman Outlines His 5G Vision, 5G Use Cases, Pre-Standards Groups Proliferate and 5G Visions Dazzle at MWC.)

The focus on 5G and SDN/NFV isn't surprising as MWC has always been the most network-focused show in the trade show circuit, leaving the gadgets to the Consumer Electronics Show. There were a number of smartphone announcements, including from LG Electronics Inc. (London: LGLD; Korea: 6657.KS) , Samsung Corp. , Huawei Technologies Co. Ltd. and BlackBerry , but most of those were on the Sunday before. Then, attendees got down to the business of keeping their networks up to date to support all these new devices and attention shifted from smartphones to IoT. (See MWC 2015: Virtual Reality Bites! and AT&T Connects Cars & Trash Cans .)

Whether you were in Spain or not last week, what was your impression of the biggest themes and hottest topics at Mobile World Congress? Let us know in the comments section below. And, take a minute to vote in our latest poll, asking whether attending MWC is essential for those who work in the mobile/wireless sector, a question that was also up for debate amongst attendees last week.

— Sarah Thomas, , Editorial Operations Director, Light Reading