A service like you are describing would likely have to be people powered in the same way as Amazon's iPhone App. I could imagine the revenue model working as either a revenue share on sold good the way Amazon does or as a marketplace for furniture shoppers and interior decorators/designers (i.e. you post some photos and a budget and decorators/designers bid to get the business of helping you find the right furniture, etc). Not sure how lucrative either of these models would be.
I was messing around with way I described the idea (partially because I thought it was a good idea and wanted to hide it a bit). The core idea is users can tag celebrities based on the clothes they are wearing and products they use. Similar to your tagging furniture idea...but I chose the celebrity niche as tagging celebs = interesting, tagging furniture = boring.
I think there's a business in there somewhere, the execution would need to be really fantastic and all the use cases and motivations well thought through. Feel free to ping me if you want to brainstorm around this (kleneway at hotmail)