YouTube:

YouTube offered the public a beta test of the site in May 2005. The first video to reach one million views was a Nike advertisement featuring Ronaldinho in September 2005. Following a $3.5 million investment from Sequoia Capital in November, the site launched officially on December 15, 2005, by which time the site was receiving 8 million views a day. The site grew rapidly, and in July 2006 the company announced that more than 65,000 new videos were being uploaded every day, and that the site was receiving 100 million video views per day. According to data published by market research company comScore, YouTube is the dominant provider of online video in the United States, with a market share of around 43% and more than 14 billion views of videos in May 2010.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". when was the first beta test for the youtube site?
May 2005