The Lensman wrote:
To the wider audience though, he's easily second only to Tom Baker.
In the UK maybe, not in the states. Doctor Who here has exploded under Smith. It's bigger than it's ever been. Under Tennant, it was still relatively unknown. For us yanks that were with nuWho since the beginning, we've been aware of the shows popularity in the UK and so understood how big Tennant was.
But Who in the U.S. was still a pretty small club that was slowly growing. It's blown my mind how much you see Who exposure now. Billboards, write up in magazines, merch displays at stores like B&N or Hastings, full page ad's in comics, and so on. Smith is now probably more well known here than Baker was, strangely enough.
As someone who's a US fan, I can definitely say this is true. I only got into Who in 2006 and there has certainly been a dramatic uprise in how mainstream it's become in the last two years. I see DW stuff everywhere, not just the examples you said, but as a student on campus, I see tons of DW-themed T-shirts and when I wear my own TARDIS-resembling hoodie, I'm always guaranteed at least two compliments. And this has all been under Smith's era.
BUT DalekJim was talking about the UK (obviously with his location being GB). Even with the new surge of Who acceptance in the US, it's STILL not a tried-and-true public institution like it is there with everyone, children / middle-aged / elderly, watch it, often together as a family unit. And there, Tennant is still a mega-celebrity.