I agree completely with KhorTose. But even with sites where only reviews of actual stays are posted, you still have to be a little careful, since one man's meat is the other's poison etc. Taking a decent sampling rather than one or two individual reviews should always give you a pretty good indication.
The one good thing about tripadviser is that it often gives you a profile of the reviewer (assuming that profile is accurate) and tells you the number of contributions made. If it is only one or two and the reviews are 5-star or 1-star, I just automatically discount them. If there are more than a couple, then a check on what the reviewer’s tastes might be and how they compare with my own to help me decide if it the reviews are worth considering.
With the reviewer Motel69 mentions, I’d rule him straight out. Why? Well, in the space of just 4 days, he reviewed 4 different Bangkok hotels. Not really an issue on its own, since he might have waited till the end of a longish trip and then submitted them all in one go. But I’d be put right off by his style of writing! Of the Shanghai Mansion in China Town where he stayed for a maximum 4 hours (arrived at 1:00 am and had a 07:00 am flight!) and allocates 5-stars, he says this –
“incredible decorated, clean and just all around awesome. to be sure, a far cry from the mandarin oriental...but i'd prefer this funky spot any day of the week.”
Yet of the Mandarin Oriental, also 5 stars, he says -
“this place is great…rooms, service - everything. really dug the authors' lounge, cool spot to grab drinks. and the limo service is a pretty sweet perk as well. top place to stay in BKK.”
So personally I don’t quite understand how the stars have been allocated. Then of the Hotel Muse (4 stars), he starts by praising it before getting critical –
“stayed here a couple times, pretty cool spot. loved the vibe and the rooms were great . . . but the staff really needs to chill-the-f-out. seriously, let’s call a spade a spade…it’s not like this is some new trendy club in the middle of the meatpacking district…i’m on vacation, in bangkok, so do everyone a favor and lose the attitude. for real. great thanks bye!”
Quite what that means, I'm not sure! But this is a young guy who is 25-34. I‘m a lot older. I'd therefore discount his hotel reviews. For others, he may be spot on. You pays your money and you takes your choice!