In late May we reported on how Twitter was on the verge of hiring its 500th employee, which meant that in just two years the company had expanded significantly from its May 2009 roster of 69 members of staff.

As of today that total is up to 572. That’s right – Twitter has recruited 73 new people in just one month.

Of course, a number of these additions were from Twitter’s acquisition of TweetDeck last month.

Putting this into perspective, as of April 2011 Facebook has over 2000 employees, but does have a two-year head start on Twitter.

And on that, and if you’ll forgive the pun, here’s the latest ‘Twitter Facebook’.

(Source: Twitter.)