[larrys]

That's just parroting of what newbies see others doing.

Back in the 90's I remember when people first started including dogs. Totally unheard of in business until that time.

As far as why (other than what I've stated) it's because it appeals to the people who are making the joke as something that they feel is cool and needed to fit in. Once again, because they see someone else doing it.

It's kind of similar to in radio the "wacky morning guy" shtick. Or even some stuff that Letterman tries to pull off. Comedy by contrast (the contrast being this isn't something you normally find in legacy established business).