What realtime search does is repeatedly scan the *last page of the auction. The last page holds the most recently listed items. Repeatedly scanning this page is a great way to find the best deals before anyone else does. Whenever it finds something under your snatch prices it'll pop up a search window listing the items and giving you the option to buy them.
Realtime search is started by selecting the Browse tab and clicking the icon that looks like a magnifying glass, but before doing that you have to tell it what to search for or it won't find anything. We do that in the Search tab.
Click the search tab and you'll see a list with a number of different search types and options available. Click on options realtime. A number of options will appear to the right, scroll down to the bottom so you can see the entire section labeled "searchers to use". Any of the searchers can be selected and you can select multiple searchers to use at the same time. I'm going to use the snatch searcher (aka snatch list) as an example so check the box beside "snatch"..
If you already use the snatch list then ignore the next bit and just use your existing list. For the rest of you, click on snatch, a window will pop up with a list on the right and dropbox with price entry gadgets on the left. Take an item you want to search for and drop it into the dropbox on the left (you can also shift-click item links into it). Next enter the maximum price you'll pay *per item* (ie if you pay 20g per stack of herbs, then that's 1g per item) in the 3 boxes beneath the drop box. Finally click "Add" to add the item to the list on the right. The snatch list will only list items at or under your price and ignore everything priced higher.
Continue adding items you want to search for to the list. Once you have everything you want in the list click the "save" button (above the list) to save the entire list. Note you can make multiple lists and you can load, edit, save lists at any time.
Ok now we have the snatch list setup we can start realtime search. First select the "snatch" searcher in the search tab and make sure you have a suitable snatch list loaded. Then select the browse tab and click the icon at the top that looks like a magnifying glass, sit back and let Auctioneer do it's magic.
Realtime search is now running and scanning the last page of the auction repeatedly. Whenever it finds something under your prices it'll pop up a search window listing the items and allowing you to buy them. This works great when you're busy doing something else in real life. Just start up realtime search and walk away from the computer. All you need to do is check the computer every now and then and make a few clicks to buy things. If the list is getting too big because it's full of things you decided to pass on, simply "clear" it and let it keep searching for new items.