My thoughts:

 - It it's **on topic** and they **disclose** that it's their own product, it's ok.
 - If it's **on topic** and they **don't disclose**, I down-vote and ask them to disclose.
 - If it's **off-topic** (even just a little), flag it as **spam**.

In an case these guys will be disappointed that all their links are marked 'no-follow' so search engines don't follow the links and score their pages higher; though users might still click through.