Since I have not seen anyone else mention it:
In the daily breakdown for the long Memorial Day Weekend, The Hangover III fell to #4 on Monday, allowing Into Darkness to climb up to #2. It will be interesting to see how the rest of the week plays out, but at this juncture it would appear that word-of-mouth is hurting H3, but helping Trek.
http://boxofficemojo.com/daily/chart/?sortdate=2013-05-27&p=.htm
EDIT: Looking at the numbers again, Trek was actually #2 on Sunday as well, but by a smaller margin.
In the daily breakdown for the long Memorial Day Weekend, The Hangover III fell to #4 on Monday, allowing Into Darkness to climb up to #2. It will be interesting to see how the rest of the week plays out, but at this juncture it would appear that word-of-mouth is hurting H3, but helping Trek.
http://boxofficemojo.com/daily/chart/?sortdate=2013-05-27&p=.htm
EDIT: Looking at the numbers again, Trek was actually #2 on Sunday as well, but by a smaller margin.