This is a very interesting subject, and something which we're all giving a lot of thought to. I've had a chat with our editor about this a few times and spoken to him again this morning to make sure that what I'm about to say is up to date...
Our owners have promised that Autosport and Motorsport.com will continue to run as separate sites with a distinct voice. They've publicly stated to the readers that they're committed to this and they've also said it to us in terms of our jobs and careers!
Most of our content will be unique to one site or the other, but there are also stories which are relevant to both audiences. The article you linked to is actually a brilliant example of this - Jon Noble spent a lot of time with Alonso yesterday afternoon and had some very interesting things to say about the Indy 500 announcement and Alonso's future in F1. Plenty of people who visit Autosport and not Motorsport.com would want to read this. I think we're providing those people with a better service by making that sort of content available on Autosport as well, and the Motorsport.com readers are getting a better experience by being able to read some Autosport content.
Our online analytics show that there's a surprisingly low crossover of readers who visit both Autosport and Motorsport.com - there are a lot more people who would have missed out on Jon's piece entirely if it hadn't appeared on Autosport than there are people who see both sets of headlines.
As for the difference between the article on the two sites - that's not an attempt to make them seem different but reflects the fact that each site has its own editorial tone and approach to stories. Articles are written and subedited differently for the two sites - both versions of the story should be how it would have looked if he was only writing for one of the two sites!