why do my tweets never come up in the twitter search?

[John Z Wetmore]

It is possible they have so many tweets on some subjects that even a "show all" doesn't actually give you all the tweets.

Try sending a tweet with a hashtag no one else has used, wait a couple of minutes, and then search for that hashtag. If you don't show up then, there is some kind of problem.

Double check whatever privacy settings Twitter has to make sure your tweets are visible to the public.