Twitter IPOI’ve been thinking about the Twitter IPO happening this week.

I’m not a financial professional and can’t comment on the financial stuff which bores me so much that my hair hurts – so I have no opinion on things like revenue and profit. Rather, I look at the big picture and invest in what I know.

Ever since Twitter launched, people have been calling the social networking service a fad. Tons of people have predicted its demise. But it seems to me that Twitter is unique enough and has a critical mass of global users to be a viable community for a long time to come.

People sometimes say that the growth of users hasn’t been as strong as Facebook. True, but with an average of 5,700 tweets per second, people are using the service.

Everywhere I travel in the world, people are active on Twitter. The company says some three quarters of its users are outside the US. Just last week in Cairo, Egypt and Doha, Qatar I met dozens of people who love Twitter and I connected with them on the service. The global aspect of Twitter should fuel growth for years to come even if the domestic market slows. There is always room for a global service to connect people from all over the world.

Twitter killer? No way!

Whenever a successful new category of social network is born, entrepreneurs line up to build a better version and pundits dub it a “killer”. How many search engines have launched as “Google killers”? How about “Facebook killers” (the most recent high profile one being Google plus)?

However, in my experience, once a social network builds critical mass, it is nearly impossible for a competitor to dislodge the number one position. Quick, what is the second largest social network in these categories? Video (YouTube #1), Photo manipulation and sharing (Instagram #1), Location based network (Foursquare #1), social network (Facebook #1), professional network (LinkedIn #1), physical product review site (Amazon #1)? They each have a bunch of wannabes. But the imitators are also-rans with miniscule market share.

While it might be easy to build a “better service than Twitter” it will be impossible to get the hundred million or so users to move over to the new network. There is only one Twitter.

There's only one LinkedIn, one Facebook, one Google, one Amazon, one Foursquare.

And there is only one Twitter.

For these reasons, I am bullish on the Twitter IPO.

Disclosure: I have an order in with my broker to buy some shares.