some people may, with good intentions encourage a product because they like it/bought it/use it in their system when it may not be the right choice for someone else for any number of reasons. That can happen even when the poster promoting the product isn’t getting any financial return from a sale.
I agree with Whart and believe his point is true. In some cases, people recommend gear they own that is an improvement over the gear they previously owned but in the broad sense of what is available in the market, the gear being recommended may be just ok. When people post their systems, it can provide context on their recommendations. It is also nice when people provide comparisons between the gear they are recommending and the specific pieces they have owned previously, to help others understand their baseline.
As with anything in life, people need to do their research and take recommendations as somebody else’s opinion and not necessarily gospel, whether the person recommending is a professional reviewer, a manufacturer, a dealer in a B&M store, or simply a poster on these forums. For example, a year or so ago I decided to try springs under my heavy speakers and I did a lot of research on the sizing of the springs and how to position, preload, and damp them. After some trial and error I found springs that work well under my main speakers and subs and I like the sound and function better than the spikes they replaced. However, I did not see a reason to jump on the Townshend bandwagon and do not perceive any reason why those should be better than what I am using with the exceptions that the Townshend products are suitable for a wider range of speaker/equipment weights and they have somewhat easier functionality, but not necessarily better performance, assuming the goal is about sonic improvement. In addition, the Townshend products cost a lot more than what I paid, even considering the cost of extra springs I purchased during my trial and error process.
Regarding dealers and manufacturers, I enjoy having them around and usually learn from their posts. Almost all of them readily identify themselves from what I can tell. However, I find the recent Ted Denney threads interesting in that folks who don’t place high importance on cables, fuses, etc., or those who don’t hear significant differences, are called out as having systems with insufficient resolution, having unsuitable hearing capabilities, or being a "naysayer" whatever that means. It sort of seems like going to a ballgame where only the home team fans are allowed in the stands.