Remember that Wilde, Penn and Jacobson only joined the TV show in late 2007. Nevertheless Leonard really didn't score very well in Google-popularity even compared with the second-draft "ducklings." Undeserved in my opinion. Wilde scored particularly well both due to her pre-House M.D. popularity and the peak surpassing even Laurie twice in size in September 2008. The former is explained by her role in the TV show The O.C. while the latter is linked with her increased screen time due to her relationship with Dr. Foreman on the medical procedural. Penn too had some earlier renown from his many appearances on TV and in movies, esp. Harold & Kumar Go to White Castle. Let's have a look at the country rankings for the actors in question:
Funny, Wilde who has both Irish and US citizenship wasn't particularly popular in Ireland but beloved in Canada. Penn, the son of Indian immigrants to the US, did score well in India. Note that Leonard's profile compared best with the first House M.D.'s post pattern: Hungary on no. 1, etc.