One example that really bugs me is eBay. eBay is a fucking nightmare to use because it doesn't let you save the filtering you do on one visit. Say you're trying to buy a certain type of bike. You're going to be visiting ebay once a day for a week or more checking out the listings. You spend a lot of time looking into the listings trying to figure out if it's a good one or not. Then you come back the next day and have to look through all the same shit !!! It's retarded. There should be a box that says "never show me this listing again" you can click (and it needs to apply when people relist the same thing, but that's a later step). You should also be able to exclude sellers, exclude by pattern match, move things to top, and save notes on listings.
The other place I really want excludes now is in google results. I do a lot of searching trying to find free download mp3's so I can listen to bands (I can't stand using the streaming media players on myspace or whatever, to check out a band I want to actually download some mp3's so I can listen to them without huge frustration). It's becoming very hard because there are so many awful sites masquerading as music content sites. If I could pattern match exclude them in the search results I could easily block out all the junk results.
I mean social search and whatnot would be nice and all, but I'd like to just have a decent way of social searching with my *self* first.
Also WTF the "t-type" word stuff in phones needs to use markov models for the whole sentence (so should the apple keyboard and all that kind of stuff); really it should be using PPMZ or a variant to make very accurate guesses of what letter you intend. It could also have a high confidence "complete word" so you can just tap a key and finish the whole word. The actual cases where there are ambiguity are very very rare, once it sees the whole sentence, usually only one of the possible words makes sense given the context.