New Post: When I query a hashtag, am I seeing the newest tweets, or a random sampling?

Hello,

I have a question about how tweets are collected when I specify a hashtag using "import from Twitter search network" and select a limit that is clearly less than the number of tweets that exist for that hashtag. For instance, if I set the limit to 500, but do not specify a date range or use any other operators in my search, am I then seeing results based on the 500 most recent tweets for that hashtag, or a random sampling?

Thanks very much for your help,

Alex