Not only is using a # (hashtag) super trendy right now, but it is a great way to get all the pictures in one place. If you create a custom hashtag, then you can click the hashtag and it will show you all the pictures that were posted (as long as they tag the picture with it).
You can create a creative hashtag just for the two of you that you can carry from engagement to wedding. Or, you can have custom hashtag for each event! Such as #bachparty201 or #Jonespartyof2.
Having trouble coming up with a creative hashtag? There are a few websites that will generate one for you!