The official stance is:
- It it's on topic, adds value to the discussion, 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. You can mark as spam if you want though. The onus is on them to add value the discussion and disclose it's their own software.
- 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.