HP is a Solarwinds customer ?
but they have HP OVO...
http://www.solarwinds.com/company/customers.aspx
There could be a small department within HP that uses the products, but SolarWinds gets to list HP as a client.
My previous organization charged back divisions for monitoring and some choose to do it themselves, because they thought they could do it cheaper and better. So when they signed contracts they were always asked if the company (large mutual fund clearing house) could be listed as a client.
Just because HP is listed, doesn't mean the product is being used in Critical environments. Anyways, SolarWinds most likely can't comment on what capacity it is being used, or the division that purchased it. That would most likely break contract or disclosure agreements.