I Twitter and I quite enjoy it. Luckily for the naming folks at Twitter, they didn't have to fight too hard to put their brand inside my head. They were the first movers.
Now, they have Yammer for company. Natural question from our point of view: how does 'Yammer' compare with 'Twitter' in the business of name calling?
When it comes to alliteration, Twitter wins with one alliterative letter more. Yes, simply speaking, alliteration is good when you're looking for a memorable name. Or plank to hold forth from. (Like so. Notice the multiple alliterations of 'alliteration'?) On the 'alliterative' front, Twitter is one alliteration more than 'Yammer'.
When it comes to other things, they're remarkably similar. Both are 'er' ending names. Both mean pretty much what they allow people to do with their applications. Both words are verbs. Neither is a portmanteau or a neologism. 'TT' sounds are just as good as 'MM' sounds. And vice versa.
So what makes 'Twitter' a better name than 'Yammer'?
Apart from the product - Twitter is easier to become part of and they have the first-mover advantage. Yammer hasn't, at least for the time being, managed to provide a better version of Twitter to us - it also sounds better ... more personal ... dignified. 'Twitter' makes us think sweet-sounding birds. Yammer, big mouths.
For the time being, I'm staying off 'Yammer'. Because the way the name makes you say it, affects how many people buy into it.