Oh OK; possibly you're not a seller. It is always a red-hot topic on the PowerSellers Board - don't know about the ordinary Sellers board. It is a well-established fact that different people, using different IDs, on different computers, can do exactly the same search, and get different results. Or the same person, with the same ID, can do the same search on the same computer on consecutive days and get wildly different results. Very frequently sellers will complain that their own items are not visible. Often people will report that buyers are asking them what's happened to their items, as they can't find them (has happened to me once.)

There are all sorts of theories for this - from the wildest conspiracy (eBay doesn't like me), to believable conspiracy  (eBay doesn't value small sellers and will promote big sellers at their expense), to believable (eBay does not have the bandwidth to support the zillions of items that are listed with it and copes by blacking out particular regions, particular sellers or buyers IDs, particular categories or sub-categories.)

For example (and these are real examples from me) - I might not sell anything for 4 days and then sell to 5 people whose first name is Barbara, or who live in a street starting with Mc, or who live in Norway (never having sold to Norway before.)  Or I will sell 4 movie posters in one day, where usually I would be lucky to sell 1 every 6 months. PowerSellers constantly report similar happenings - way too many to be coincidental.

Anyway I could go on and on. When you sign the eBay selling agreement now, it does not guarantee that your items will be visible at all times. Or to all potential customers.  Personally (disclaimer - I am a complete dodo)  I think eBay is seriously lacking in both bandwidth (it got rid of a lot of its bandwidth some time ago to save costs) and technical expertise (the password fiasco and very recently the "blackout" last week which affected me personally and millions of other eBayers.) eBay claims "250 to 300 million searches are being made on eBay each day"

http://www.ecommercebytes.com/cab/abn/y14/m09/i05/s02

Many PowerSellers report that their sales have nosedived in the last few months, compared to results from last year or even several years ago. And that their sales are very patchy, with nothing for a week then a great day or 2 of sales, as though "The Tap" was being turned on and off. However it's their platform, you play by their rules, and you stay here for as long as it is the best site for you.