If you see a uke on eBay and want it and you have the money buy it, you can either do a buy it now or take the risk to get in a winning bid in the last 40 seconds.Either way, don't wallow around in UU opinions.
If you see a uke on eBay and don't want to buy, don't do anything. Don't post links or try to help out buyers, in the end you wont help the buyers. Most people know how to set up a search on eBay, part of the fun for them is finding the item and making the bids. You spoil a lot of the fun and attract lazy buyers by posting links and comments on UU.
The best time to post about an eBay uke is after you win the auction or after the auction closes. Then you wont be spoiling anyones' ukulele searching and buying fun. Also you will be helping people learn about eBay without spoiling their collecting fun.
This is just my opinion.