Check http://www.sqlskills.com/BLOGS/PAUL/post/A-SQL-Server-DBA-myth-a-day-%28930%29-data-file-shrink-does-not-affect-performance.aspx

>Once, I reindexed those two tables, I ended up with the result as shown as in the attached file. So, it saved 3 MB.
>
>The rest of the report in the first picture was all zeros. But, as you said, they were under 1 MB. So, adding them all together would probably sum it all.
>
>As a test, if I remove all the records in the Hit table, which is only a log that lives for a few days, I end up with the image #2. But, the MDF is up to 57 MB now. But, if I shrink the database, it goes down to 19 MB. But, we shouldn't do that. Or, is it that the MDF size was in fact lower but still not refreshed in Windows Explorer. And, when I did the shrink database, it forced a refresh in Windows Explorer?