I'm pleased to announce the launch of the Transit Layer on Google Maps in more than 50 cities around the world making it easier for citizens and tourists around the globe to access public transportation line information in their cities.

To switch on the layer go to the More button and select the Transit tab:

http://google-latlong.blogspot.com/2009/01/new-ways-to-get-around-with-transit.html#links

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From TechCrunch:

Today Google added a new feature to its extremely useful Maps service, allowing users to quickly view the layout of public transportation systems in more than 50 cities. While Google’s Transit site has offered automatic trip-planning for a number of areas for some time, the new feature makes it easy to determine at a glance if public transportation is even a viable option.
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http://www.techcrunch.com/wp-content/uploads/2009/01/londonshot.png

In fact it's absolutely not related to Google Transit. They just added some "my maps".
Bad google, bad.

Surely that was the point of My Maps, Tom?

My Maps = to draw lines on the map.
Transit = calculate travaling time and directions.

When I read this news, this thread in the forum, it's not related to "Transit" for me, because you've only lines, no more than before ;)