This user, seems to promoting a 'private company', they puts a private company name with their logo in user profile, I don't know is it allowed or not, please let me know is it allowed or not.
AFAIK anybody can use stackexchange sites, as long as they follow and/or accept site rules and policies.
As far as AU is concerned, anyone with a Ubuntu question can ask a question, it may be a person, a group of friends, It can be a company or even a government. For the same reason, a user may be a company and therefore they can promote(in their profile) and display themselves as who they are, as in case of the aforementioned user.
Not to mention that as @dan said, they should not spam the site or promote there products in questions/answers/comments etc.
On the same note, a user can also be an intermediate between other non-English users and the site. In my case, almost 50% of all questions I have are from either Indian, Spanish, French or even English friends that because of one reason of another don't know how to create a question with the right words or post the issue in a manner that can get help.
I have helped a little over 100+ New/Old Ubuntu users with this method and this has also helped future visitors with the same questions. A Win-Win if you ask me. So as long as the account is used by following the sites rules and policies, the account will not be closed or issues a warning.