Being a smart twitter person, you include hashtags to explicitly target the groups you want your tweet to show up in. Imagine your surprise when, after posting your tweet, that your tweet doesn't show up in the list. This is the problem that was presented to me just today. I honestly did not know why this would happen so I did what every good technology person does, I searched it. To save you time from searching, you can read the full answer or, better yet, here is the summary for you.
The answer lies in the fact that Twitter defaults to the "Top" search results and not "All" search results as seen here:
If you change the filter to "All" search results as seen here:
By clicking "All", you should see your tweet in the list. Of course, if your tweets are protected (by default they aren't) you will need to unprotect them for them to show up in the public list.
This begs the question, how do I get Twitter to put my content on the "Top" search results. While I don't know of any gauranteed way, Twitter does seem to give indications. In light of Twitter's recommendations, and from looking through multiple lists of "Top" versus "All" there is definitely a correlation between having multiple hastags and NOT showing up in the "Top" search results. It seems Twitter is trying to ensure the content is relevant to the list results as oppossed to someone trying to get on multiple hashtag lists with a single tweet.
So, keep on using those hashtags, but if your goal is to show up in the "Top" search results, limit yourself to using just one hashtag per tweet. By all means, leave a comment indicating whether this solves a problem you have experienced. Also, if you have other great Twitter insights leave a comment sharing your knowledge so others can learn from your experiences.
The rabbit hole runs deeper than first thought and there are some other issues that could be causing your tweets to not show up in search lists. After doing more reading, I have come across some information from @tweetsmarter that I felt very useful and wanted to share. If the recommendations above on hashtags doesn't seem to solve your issues, be sure and check their information also.