Jeremy Hobson:Even if you don’t use Twitter, you can’t deny the impact its 140 character messages have had on real life events. The Arab Spring, for example, may not have happened as quickly as it did without ordinary people being able to communicate with each other via Twitter. Well, the social networking site has just announced it will block some tweets — particularly those that violate laws or bans on speech in certain countries.

Marketplace’s Jennifer Collins reports.

Jennifer Collins: Twitter says it will now be able to select tweets with illegal content and stop users in certain countries from seeing them. In the past, if a tweet was deemed illegal, the company had to delete it across the entire world. In a blog post, Twitter gave an example of pro-Nazi speech. It’s banned in France and Germany but legal in the U.S. because of the First Amendment.

Analyst Richard Holway with Tech Market View says this is just the latest tech company that’s tweaking the way it that it works in order to get more users abroad.

Richard Holway: If you look at many of the decisions they’ve been taken for purely commercial reasons.

Twitter hinted in its post that that it wouldn’t block speech like Tweets used by protestors in the Arab Spring. But what about China?

Holway: People still operate in China, and they do it because it is going to be the largest single marketplace for products, everything from Apple through to Google.

Twitter has been blocked in China since 2009.

I’m Jennifer Collins for Marketplace.