Let me first say that I totally agree with eBay's new Safeguarding Members' IDs policy, because it stops fake second chance offers dead!
Sellers of high value items, like myself, suffer greatly from scammers sending out fake second chance offers to underbidders. The scammers had the underbidders' IDs from the items bid history, and could see just how much that person had bid. So it was pretty easy for them to send out a fake email which looked identical to eBay's own. Too many people have fallen foul of this, and enough of them, sellers and bidders alike, have complained about it that eBay have finally taken action.
This is a controversial decision which many think gives the seller greater scope for shill bidding. This simply isn't true.
In the new style bid history, there is a link to each bidders' bid history, showing their activity not just with the current seller, but with any seller. So if a seller is using a second account to push up the price, which is what shill bidding is all about, it will show. You can see how many times the bidder has bid on this seller's items, how many other sellers' items they have bid on, and other such information which was previously hard work to compile from the various searches available in Advanced Search.
In fact, a glance you can see the whole bidding activity of the bidder, and in far more detail than previously readily available. Coupled with eBay stopping private feedback, this actually reduces the scope for dodgy sellers to push prices up by shill bidding.
It has also been said by others that shill bidding is a "lesser" crime than fake second chance offers, as people who enter their maximum bid, and stick to it, can't be pushed higher by shill bidding. Where as with fake second chance offers, people have been ripped off for hundreds and even thousand of pounds. I'm not so sure I agree with this, but I do understand the sentiments.
So, with the bidder's identity hidden from general view, is it still possible to see if a seller is shill bidding, or getting a mate to regularly bid up their auctions? The answer is basically yes:
1) Using the link provided by eBay you can see how many different items and the number of sellers the bidder has bid on. If the bidder has only ever bid on one seller's auctions, but has bid on many different items, you can draw your own conclusion.
2) If a high value item is re-listed a good number of times, I would suspect the dodgy seller has "won" their own item in their efforts to push the price higher than genuine bidders are willing to pay. Remember there are a number of legitimate reasons why a seller has to re-list an item once or twice, so this isn't a hard and fast rule.
3) Common sense. Never underestimate your gut feeling.
Finally, not all sellers of 99p no reserve auctions are dodgy sellers; some of us use it as a sales pitch to generate more interest in our items :-)