I'm the old man in the Tivix office, so I’ve seen a number of significant shifts in the technology landscape in my career. But I’ve never seen anything like the velocity with which users have switched over to mobile devices today.

Just look at these stats from earnings announcements in the past couple weeks:

Facebook, in their 4th-quarter earnings announcement, said that 53% of their advertising revenue in the quarter came from mobile. This is remarkable, given that in 2012 they had virtually no mobile presence (partly because they believed that mobile traffic was difficult to monitize) (source: NYT).

Yelp, in their 4th-quarter earnings disclosures, said that 59% of all Yelp’s searches were via mobile and 47% of their ad impressions were served on mobile device. (source: Forbes).

Apple, notorious for having less than an 8% market share in computers, has now executed a spectacularly brilliant end-run. If you count iPhones and iPads as “computers” (which they arguably are), Apple’s unit sales now exceed all Windows PC makers, combined. Think about that for a moment (source: Andreessen Horowitz).

It's an amazing sea change. And we're right in the middle of it.