In most cases I must disagree with the assumption that reputable companies profit in any way from spam. Most such stuff is simply using recognizable "names" to attempt to get people to "click" so that they can be connected to a fake site that looks like a reputable one, sometimes to attempt to "social engineer" you into revealing personal information, but often just in order to get a bot onto the user's computer.
A SPAMMER makes nothing from sending you to someone else's real site, so if it looks like one has done this you almost certainly are at a counterfeit website, or - extremely rarely - the spammer has managed to infect a real company's site.
If a bot/worm can be downloaded to you, the bot usually will later reconnect to another site or to any other infected machine to download the really malicious stuff that steals your personal data AND/or uses your machine to send more SPAM. Phony sites that spammers send you to usually get shut down fairly quickly, but every machine they've infected can host a new fake web page, to be used to spread the infection.
When you buy real stuff from real websites that are not owned by the producer of the product, the website DOES NOT LOOK LIKE the site of the producer, it looks like the site of the re-seller.