I particulary like the fact that you can specify as destination everywhere and have a look at a certain period. This is because you do not really know where you want to go but you know the kind of place you want to go. For example if you live in Ireland you do not want to go to Norway, UK.
Can it be possible when you specify an open search with ‘everywhere’ to monitor a list of favourite countries? It happens to me that when I put ‘everywhere’ I am very disappointed to see that the cheap destinations from Ireland (Dublin airport) are: Norway and the UK.
Then if I am looking for the month of August and I live in Ireland chances are that I do not want to go to Norway but to a set of cool warm countries such as: Italy, Spain, Greece, Malta, Cyprus etc…
The advantage of this is that you can surprise the person suggesting a destination he/she would like to go but does not know (e.g. Cambodia, Thailandia, Chile for me personally speaking).
From a technical point of view you implement this using data mining, looking at the destinations where people living in Ireland with my age profile (or more demographics) go.