well it depends on which contry they are searching from and which facility they are using,
Like when
toolbar is installer then it ask's whether you want local search (.co.in in my case) or global search (.com)
what i do is i keep it global but my firefox toolbar always fetch results from
.co.in
so if i want .com results i go for the
toolbar search options.
So basically it all depends on browser setting's and personal preferences but most people watch results from
.com IMHO.